Coolant leak ruins day - new hoses?

[dionphaneuf]

I was up until the wee hours of Monday (Tuesday?) morning replacing my rear pads and front pads/rotors, spark plugs (non resistive repalcing resistive) and tidying up some other things in anticipation of a road trip in NorCal on Thursday. The car went back together without much issue and was running beautifully through Sonoma county, catching BMW 2002s and even some Porsche 911s without breaking a sweat. Temps were in the 80s (F), and my temp gauge was parked just below 80 deg C as usual. A few miles outside our lunch stop in Windsor, my gauge started to creep up and I got a little worried. I've never much trusted temp sensors, viewing them as more binary/directional and not absolute. Once I approached the mark between 80 and 120 (100?) and the rate of climbing wasn't slowing down, I knew something was up. Before I could pull over white smoke was pouring out the hood and vents; I shut the car off before it got above 100, opened the hood, and removed the enginge covers.

I eventually found the left (drivers side) coolant heater hose had burst on the engine side of the fire wall. It runs from the back of the left head into the cabin, with a T feature as a bypass. We towed the car into town, but the nearby MB dealer couldn't get the part for a few days and rather than risk using hose tape or building a replica w O'Reilly hoses, I brought the car home on the back of a flatbed. I'm fairly certain the head/motor is fine, but I'll run a compression check to be sure. The hood underpad was soaked as you'd expect, but I think it's fine.

The hose (124 830 7696) is available in a day or two from the dealers; it seems prudent to replace the RH hose (I cannot find the PN of the RH side version of this hose) and flush coolant while I'm at it, but I'm not sure where to stop. Upper/lower radiator hose? Hoses on engine block? Cross car bypass hose under cowl/near wipers. I have a new reservoir, float switch, and reservoir cap which I'd meant to put in around this time anyway. Scanning the forums it seems these heater hoses are prone to bursting, likely bc they sit in a high heat area behind the engine and see hot coolant, whereas the rad hoses see the cooling air off the radiator which might help reduce thermal ageing. The car has 230k miles but has spent its entire life in CA; I'd love to regain 100% confidence in it and not have this occur again, but I'm mindful of this becomeing a time consuming and expensive exercise.

 

[gsxr]

If temps remained below the red zone (120C) and you had no massive coolant loss, the engine should be fine. You caught it in time.

Rubber parts have limited life spans, check the other rubber bits too... there's a hose on the opposite side that would probably be good to change at the same time. The rear heater hoses exiting the engine and upper radiator hose are the main ones to worry about, along with the aeration hose from radiator top over to the plastic reservoir. The lower radiator hose wouldn't hurt, but this sees lower temps than the rest of the system. The small ones behind the main firewall should be ok, ditto for the ones at the washer tank.

Did the failed hose have any visible damage, or was it swollen, or anything else?

One way to help avoid this is periodically pressure-testing the cooling system (when cold) to at least 1.0-1.2 bar. Any marginal hoses, clamps, or radiator seams will become evident. Once you get new parts installed, you shouldn't need to worry about it again.

 

[dionphaneuf]

I definitely lost a bunch of coolant, the question is how much. I'll find out when I fully drain the system. The hose burst was burst over an inch long section behind the head. Other parts of it look worn too, with some gouges and cords starting to become visible.

Do you know the PN of the right side hose? Can't find it on Pelican. The overflow hose looks to need the 6x9mm bulk hose. What about the ones on the engine block - going to the water pump or intake manifold?

As an aside, the windsor pick and pull had everything but what I needed...a 94 S600, a 97 S320, and a 97 E420. An interesting collection to be sure.

 

[gsxr]

Please don't use Pelican to look up part numbers. You'll either find stuff missing, or get the wrong part. The EPC is the ONLY source for part number. Then look up the part numbers at dealer sites, not Pelican.

Passenger side hose should be 124-830-54-96, photo below. See if you can find the part number on the old hose to confirm.

Driver side should be 124-830-76-96 if you have a 1992 or 1993 500E.

Overflow hose is not 6x9, it's 8mm ID, 15mm OD, p/n 000000-000734. This is sold by the meter via aftermarket sources, and you need around 1.5 meters. If you buy from the dealer, it should be a single 2-meter length. Meaning, don't buy 2 if buying from the dealer, but you need to buy 2 from aftermarket vendors.

Hose to intake manifold and 90° hose at t-stat housing are a good idea to replace when the thermostat is changed, which should be every 7-10 years at most.

 

[gerryvz]

I had a similar situation that happened back in 2013, though it was caused by a radiator leak.

I lost more than 50% of the car's coolant.

Get both of the heater hoses from MB only. Get the upper and lower radiator hoses from MB. You can find all about how to replace them in my recently completed Project Journal on Top-End Refresh. If you read through that thread, there are a couple of listings of part numbers that I ordered early in the process, and the heater hose part numbers (both of them) are listed.

DO NOT BUY THE HOSES FROM PELICAN PARTS. Get them from a mail-order MB dealership (genuine parts) such as mboemparts.com or getmercedesparts.com These will be significantly discounted. Pelican Parts does NOT have good pricing, nor can you get all factory parts from them. They are not worth using for parts orders.

 

[gerryvz]

First (driver's side) heater hose replacement:

RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

See my previous post — I added some photos at the end. It looks to me like the seal is nearly flush with the timing cover. No question it is original. I will do the latter like you did, but will also gauge with the seal tool.

www.500eboard.co

Second (passenger side) heater hose replacement:

RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

Spent about an hour out in the shop on Sunday -- time was cut short by Laura's family coming over for Mother's Day. So, I limited my time to a few, small operations. First little task was to continue preparation on the red powder-coated valve covers. I added a factory MB yellow sticker on the...

www.500eboard.co

Note that my car is a late (facelift) car, so the driver's side hose on my car may be different than yours.

 

[gerryvz]

Driver side should be 124-830-76-96 if you have a 1992 or 1993 500E.

The VIN cutoff for cars using this hose goes up to 096886, per the EPC, so early 1994 model year (facelift) cars would also use this hose. My 1994 car is 052693 and used the same hose part number that the @gsxr mentioned above.

 

[dionphaneuf]

Thanks for the help all. I put together my order last night and MBOEM parts is quoting me a few weeks, regardless of shipping options, if I get all the hoses. My local dealer has the broken hose much sooner (sfbenzparts.com), so I may just replace that (and the $0.50 dash grommet) this week while waiting to mid Oct to get my other parts.

As this project expands in scope from the broken hose to all hoses and I read some threads I'm wondering if I also ought to do the thermostat 'while I'm in there'. It was last done in 2013 at 205k miles (and before that at 143k mi in 2002), along w a coolant flush and water pump replacement. Car is at 232k miles now. I think I'm fine to leave the pump alone based on age and mileage, but will do the t stat for age and also function, using Behr 116 200 03 15 on my car. My car almost always runs around 80C, which seems like it's cooler than it should be and indicative of T stat issues. Temp did rise to ~100C as coolant leaked.

Edit: Forum reading reveals an old/malfunctioning T stat usually manifests itself in slow warm up of coolant, and not necessarily the engine running too cold. Based on my operation my T stat is probably fine but I'll replace proactively. Anything else I ought to do while I'm in there? I have a new reservoir, cap, and level sensor to go into the car too.

 

[gsxr]

An old/malfunctioning T stat usually manifests itself in BOTH slow warm up of coolant, and also the engine running too cold, in low ambient temperatures. Regardless, I think it's a good idea to replace proactively every other coolant change, or 7-10 years. $20 is cheap insurance. Might as well spring for a new 90° hose unless it was replaced in 2013 with the t-stat.

There are a couple other discount dealers you may want to check into, without weeks-long waiting periods. MB Beaverton, MB Fresno, and a couple others on the left coast. Unless you already ordered from Napsterville?

 

[nocfn]

I am currently replacing the rubber and fully drained my system. The pic below is the intake hose, original and wearing from the inside out. Replace your hoses.

 

[dionphaneuf]

Yeah I have every 'underhood' hose on order - left and right side heater hoses, upper and lower radiator hose, radiator to expansion tank hose, and the two engine hoses (manifold and pump to thermostat). I think that should cover it for now, I know there are a few more behind the firewall on the passenger/R side but they seem quite challenging to access and likely not as worn. Also thermostat.

I'm open to being convinced otherwise, tho. In for a penny, in for a pound.

 

[dionphaneuf]

Hose (heater hose only) came in finally and installed it yesterday. Filled about 1 gal of coolant into upper rad hose, then 1 gal into reservoir. Started car and added a bit more as reservoir was 'burping'. Car was running pretty rough at first....stumbling, engine was moving a bunch. No smoke out tail pipe. I turned on heater (worked fine) and let things warm up over 20 mins or so then took it around the block. It ran fine above any creeping speed, but was lurching a bit at idle while in D. RPMs on dash stayed constant at around 500 RPM, engine got to a bit below 80C (both good), but oil pres was fluttering at idle around 1.5 Bar. It usually settles at or below 1 once warm. When I looked at the engine while running it was not moving as much and didn't seem to be stumbling as much, but not as smooth as it was before. During the intial warm up I briefly shut it off to check oil and it was below the mark on the dip stick, adding just over a quart brought it back to right around 1/3rd of the way up. Hoping this is just an intermittent issue but not sure what to check next. Would like to run a compression test at some point for my own sanity, altho these symptoms point to something else.

 

[gsxr]

Rough running sounds like the typical ignition issues... how old are caps/rotors/insulators?

Temp should never be under 80C once warmed up, if so, the t-stat may be bad (or, gauge is off).

Idle RPM in gear is normally 500, in P/N should be ~650rpm.

Oil pressure at hot idle generally should be over 1.5 bar unless you are using very thin oil (what visocisity?), OR the pressure sender is old/original.

 

[dionphaneuf]

Caps and rotors are fairly new. Redone in 2017, 10k miles ago along w transmission and motor mounts, so I think those are safe. Plugs are correct and brand new. Oil is Mobil 1 15W-50, atho I usually run Castrol 20W-50. I planned on replacing the thermostat as part of the coolant system refresh; it's only 7 years/30k miles old but can't hurt. Interesting to hear you say temp gauge may be off as I have been told by others that it seems to run 'cooler' than other E500E and R129 M119 vehicles.

Part of me thinks this may be a vacuum leak, will also check those. A hose could have easily been knocked off during air cleaner removal or reinstall during the road side inspection.

I'm going to do a compression test tomorrow after I pick up an external starter switch - saw the procedure on another thread and tried to read up more but wanted to clarify so I don't make a mistake. One of the crocodile connectors of the starter switch will go to the inboard most lug of X4/10, the collection of 4 lugs (2 small flanked by 2 large) on the left rear corner of the underhood, just in front of the dash panel. The other side of the starter switch goes to X27, a large cigar shaped connector clipped onto the rear of the large control module just forward of X4/10. I separated this connector and got a picture of the inboard side of this connector (going to the engine bay) that has a male feature, but I believe I got this incorrect - I should attach the crocodile connector to the outboard/female side of this connector. All of this is after getting the engine warm, all 8 plugs pulled, w a tester loosely screwed into the spark plug well. Crank 6-8 times on each cylinder.

 

[TimL]

My caps and rotors were done not even a year ago because of rough running engine. 7 months and 3k miles later they had to be done again. All I’m saying is, don’t rule the caps and rotors out from your checks/diagnosis.

 

[gsxr]

My caps and rotors were done not even a year ago because of rough running engine. 7 months and 3k miles later they had to be done again. All I’m saying is, don’t rule the caps and rotors out from your checks/diagnosis.

This: ^^^

There have been increasing reports of defective caps or rotors, seems like over the past few years. I don't know if they are actually failing, or if it's some other combination of conditions causing issues, but don't assume 3-4 year old components are still ok. This is when it's handy if you kept the old parts (assuming they weren't junk).

Interesting to hear you say temp gauge may be off as I have been told by others that it seems to run 'cooler' than other E500E and R129 M119 vehicles.

While not common, the temp sending unit can drift lower over time. Best way to ch eck is comparing the dash gauge to live data from a digital scanner, which pulls from the 4-pin sender right next to it. The two (actually, three) readings should all be within ±2° of each other at most.

Part of me thinks this may be a vacuum leak, will also check those. A hose could have easily been knocked off during air cleaner removal or reinstall during the road side inspection.

Definitely check the entire vacuum and PCV system for leaks.

I'm going to do a compression test tomorrow after I pick up an external starter switch - saw the procedure on another thread and tried to read up more but wanted to clarify so I don't make a mistake. One of the crocodile connectors of the starter switch will go to the inboard most lug of X4/10, the collection of 4 lugs (2 small flanked by 2 large) on the left rear corner of the underhood, just in front of the dash panel. The other side of the starter switch goes to X27, a large cigar shaped connector clipped onto the rear of the large control module just forward of X4/10. I separated this connector and got a picture of the inboard side of this connector (going to the engine bay) that has a male feature, but I believe I got this incorrect - I should attach the crocodile connector to the outboard/female side of this connector.

That diagram is not accurate - don't use it! The large cigar-shaped connector is mis-labeled as "X27". The cigar connector is for the cam position sensor, that goes to the EZL.

The remote starter switch does connect to the large terminal of X4/10, which is a direct line to the battery. But the other side of the remote switch goes to X27, which is DIFFERENT connector terminal, not shown in this photo, which is also totally different between 036 and 034. On the 036, X27 is a rectangular, 3-pole connector located directly below large cigar-shaped connector. Don't mess with the cigar! The cylindrical connection you see in the FSM is not X27, it's the factory tool shown below (much smaller cylinder/cigar). Unplug the female side (S) and connect to the center terminal (of 3) on X27, which is bolted below the cigar.

All of this is after getting the engine warm, all 8 plugs pulled, w a tester loosely screwed into the spark plug well. Crank 6-8 times on each cylinder

The tester has to be screwed in tightly enough to not leak air, but not so tight it won't unscrew by turning the hose. You can use an adapter pipe to avoid this potential problem, but the readings will all be lower than actual - which is fine, as you are looking for highest vs lowest readings, not a certain number. Also, crank until the pressure stops increasing. This is usually by 6-8 compression strokes. I generally go over each cylinder twice (i.e., 1-8, then start over and do 1-8 a second time, comparing readings).

 

[Kyiv]

My caps and rotors were done not even a year ago because of rough running engine. 7 months and 3k miles later they had to be done agai

I can second this experience

 

[gerryvz]

My caps and rotors were done not even a year ago because of rough running engine. 7 months and 3k miles later they had to be done again. All I’m saying is, don’t rule the caps and rotors out from your checks/diagnosis.

I can second this experience

See what I just posted here: Ignition problem traced to faulty insulators behind distributor caps | M119 Engine

 

[dionphaneuf]

Thanks so much for all the helpful suggestions, especially on the compression test procedure Dave. I've had issues before when interpreting the FSM before, and glad this didn't lead to a costly mistake. Picked up a remote starter switch at my local Autozone (shudder) today and managed to run a compression test after driving the car. Thankfully values looked good, to my eye - all right around 180 psi (give or take 5). I've left the car apart in my garage and will fiddle with the vacuum system before going all in on caps and rotors.

 

[gsxr]

10psi from highest to lowest is excellent. Spec is ~22psi max.

 

[dionphaneuf]

Looked thru my now google doc'd service records and found that while the caps and rotors were replaced twice in the last 10 years/30k miles, the insulators never were. Kinda surprised/disappointed as this was done by Winco, which I thought was a good shop, although they also used resistive plugs. Darn. Anywhos, parts now bought and on their way to me. My Sister in Law has been very generous and let me drive her car in all of this, but I'd like to not extend this any further than I have. Am I doing any damage driving this car as is today, w crappy insulator and rough running?

FYI on parts, cheapest I could find
Beru caps on eBay, 2 for $150: For Mercedes R129 W124 W140 500SL S500 Pair Set of 2 Distributor Caps Beru | eBay
Beru rotors (2x$60) and Bosch insulators (2x$54) from FCP Euro, can't find these cheaper elsewhere

 

[gsxr]

Looked thru my now google doc'd service records and found that while the caps and rotors were replaced twice in the last 10 years/30k miles, the insulators never were. Kinda surprised/disappointed as this was done by Winco, which I thought was a good shop, although they also used resistive plugs. Darn.

Very few shops replace the insulators, unless they deal with the M119 enough to know it's needed to prevent warranty claims. Ditto for the plugs. I'd have been more surprised if they got everything correct!

Am I doing any damage driving this car as is today, w crappy insulator and rough running?

If it smooths out at speed and/or when warmed up, nope, shouldn't hurt anything.

FYI on parts, cheapest I could find Beru caps on eBay, 2 for $150: For Mercedes R129 W124 W140 500SL S500 Pair Set of 2 Distributor Caps Beru | eBay

That's the best price I know of as well.

Beru rotors (2x$60) and Bosch insulators (2x$54) from FCP Euro, can't find these cheaper elsewhere

Don't buy those. You'll likely receive the "new" Beru rotors, reboxed orange Facet. NOT the "old" Beru rotors which were reboxed OE/Genuine. Right now, the only rotors I would buy are OE Genuine from your favorite MB dealer. But they are going to be ~$75 each.

 

[dionphaneuf]

Are you sure? These appear OE to me. If so I'll cancel em and get OE from the dealer, $82.50 but worth it.



Pelican has the caps listed as from Beru w much faster shipping than the eBay supplier.

 

[gsxr]

Are you sure? These appear OE to me. If so I'll cancel em and get OE from the dealer, $82.50 but worth it.
View attachment 115299

Someone reported last week that they received the orange Facet rotors, in the Beru box, from FCP. They just haven't updated their website yet with a new photo and COO. You could try contacting FCP to confirm. The new part number is 1 digit different. There's a chance you could get the correct ones but you'd have to wait and see...

 

[gerryvz]

The Beru EVIL 1831 are going to be the orange ones. It's the EVIL 183 that are the black units.

If you get black ones, consider yourself lucky !! If you get orange, send them back to FCP for a refund, and get the MB rotors (real deal DoDuco).

 

[dionphaneuf]

Confirmed by phone today that FCP euro shipped me the 1831 parts. Ordered the good rotors from my local benz dealers parts website

 

[gerryvz]

Well, at least you can send them back for a full refund. Or keep them as spares.

 

[dionphaneuf]

I took my car on a longer drive this weekend, giving the 08 Camry generously lent to me by my SiL a bit of a break. I'd taken the car apart a bit after the compression test, so after putting it back together I thought I'd let it run for a bit in my garage without the air filters on and it idled without any stuttering or hesitation. I then put everything back on and got some minor hesitation, at which point I drove the car about 25 miles to a car meet. Getting off the freeway on surface streets, I noticed some of the same roughness at idle, although not as severe. After an hour, we then drove the car another 30 or so miles, and it actually seemed to idle quite smoothly by the end of the journey, before returning home an hour or so later with more smooth driving. Most of this pushed me in the direction of caps/rotors/insulators...I bumped into another 500E owner at the meet and he thought the issue was likely rotors as well, given the improvement w driving time. The thesis is that these got 'wet' or at least exposed to some moisture when the hose burst and the underhood absorber got soaked, along w the rest of the engine bay (I lost something like 1.5 gallons of coolant to steam and leaks).

This piqued my interest, and not being able to leave well enough alone I thought I'd investigate the cap/rotor/insulator/cam seal condition prior to my replacement parts arriving later this week. The caps had some minor amounts of material but didn't look too bad, but the insulators were very old and dirty. They are yellow parts and could spin in their seat easily, and while I cleaned them as best as I could I wasn't thrilled w the end result. I grabbed a crappy photo w my iPad of the area behind the insulator on the right side and it looks not terrible to me, but could be better. The car was cold by this point and drove okay afterwards, but not as good as earlier in the day when it had warmed up for some time.

 

[gerryvz]

It seems more often than not that the often-overlooked insulators tend to cure the problem. I bet you will find same.

 

[kegmankipp]

Might as well Take Jono’s advise and get the cam seals from MB while you’re in there. I just picked some up for $9 for the pair for Genuine.

 

[dionphaneuf]

I'm looking at doing a compression test on an M117 126 car and having trouble w the FSM procedure as many of the connectors don't show in the locations as sketched - that temrinal block is by the oil filter, whereas the closest I can find is by the battery tray/wiper fluid. This would let me do the test w a remote starter, but TBH it may be easier to just pull the ezl connector to the cps (green wire) and then just crank.



Edit: realizing I should post this in 126 board, sorry