500E Running Hot - Water Pump, Viscous Fan Now Solved

[jaymanek]

Hi All,

I am a UK car Owner here in the UK and the reason for my post is to thank the author this thread in the WIKI as it saved me so much time and hassle:

http://www.500eboard.com/forums/showwiki.php?title=Viscous_Fan_Clutch

I have owned my car since 2008 and it has given me very little trouble although always run a little hot for my liking... Previously I had already replaced the radiator, A/C Condensor & fan Switches and Fan Relays.

This summer the car started to run over 100 and would climb beyond in traffic so I decided to tackle the water pump, thermostat and viscous fan clutch in one hit...

Well the water pump was the most difficult... Of course the radiator, fan pulleys and water pump pulleys must be removed. Also the main crank pulley balancer has to be loosened off... Do not need to remove centre crank bolt but do need to remove the 13mm bolts to be able to loosen the vibration damper off, as the bottom water pump bolt cannot be removed otherwise...

There is a guy on here that claims to have done it without removing this but I really cannot see how!
Its listed as a 4 hour job and it took me that and more to do

Also worth nothing that my "Vemo" fan clutch lasted less than 100 miles before it split and released gunk all over my engine bay... I was not happy... This has been returned and I have now fitted a Febi Bilstein part which I hope will last longer.

I think my root problem was the water pump as even with the broken fan clutch, with just the new water pump the car sat at 80 degrees most of the time.

I used a genuine MB water pump...

Very satisfied now as its been something ive been wanting to get sorted for years.

 

[gsxr]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Also worth nothing that my "Vemo" fan clutch lasted less than 100 miles before it split and released gunk all over my engine bay... I was not happy... This has been returned and I have now fitted a Febi Bilstein part which I hope will last longer.

Congrats on the fix! I would keep a close eye on the Febi fan clutch. It may be the same as the Vemo. The only known-good clutch is the original Sachs / Horton. There have not yet been reports of ACM clutches failing, and the ACM will at least disengage at high RPM (which the Vemo did not). Hopefully your Febi clutch was made by ACM and not Vemo....

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Oh great

Ok will keep an eye on it... But it felt better made than the vemo one to me..

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Good work. I concur with GSXR with regard to the FEBI fan clutch. I would recommend ONLY using the factory or confirmed OE manufacturers' fan clutches. FEBI is often Russian Roulette.

Did you find any visible issues with the water pump that would have indicated it wasn't working well? Did you replace with a factory MB water pump, or go aftermarket?

Are you the jaymanek who is a regular on the Benzworld 126 forum ?!?

Cheers,
Gerry

 

[samiam44]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

"There is a guy on here that claims to have done it without removing this but I really cannot see how!
Its listed as a 4 hour job and it took me that and more to do "

There are 2 types of harmonic balancers on M119's.. later style is a single bolt- no center hub. 1995 and sub engines it maybe possible. I think 5-6 hrs is normal. This is a good time to replace the front seal.. or do it a second time later.

" I used a genuine MB water pump... "


Mike

 

[Christian_K]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

This is a good time to replace the front seal.. or do it a second time later.

For the Front seal you have to remove the Hub from the crank (also remove the 400NM Bolt - fun without laaarge tools or to remove radiator+condenser), as the front seal seals against that Hub - and not against the crank.

 

[Jelmer]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Thanks for the write-up, now I'm 100% sure I'm going to replace my water pump!

Did you find any visible damage or wear on the old pump?

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Hi,

No there was nothing visibly wring... I would have taken pics but it had to be sent back to MB for a surcharge refund.

 

[doolar]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

The water pump was changed on my car just before I got it, and I've never driven a MB with such a stable water temp, even in hot weather and inspired driving it rarely goes over 90. It can also sit on idle in 30 degrees C, and it will take a loooong time for the fan to kick in. That's one helluva powerful waterpump!

My dads 500E is far from this cool (in the cooling department that is) with the fan running earlier. Probably original pump on his car.

Bottomline - get it changed...

 

[samiam44]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

As Christian noted,

it does take some tools to R&R the seal- but this IS the time to replace a 20 year old front seal.. even if it is dry. You've done 90% of the work to get at it..

Crank lock is not expensive on ebay ~100. You'll need a 27 mm socket or equivalent US size. Big breaker bar. I have a big torque wrench, but if you do not, you can weld up a multiplier and use it. I used my 600 ft-lb 3/4 drive torque wrench.

I said do it now- because I had to repeat the process to do the seal less than a year later.


Michael

 

[gsxr]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

The water pump was changed on my car just before I got it, and I've never driven a MB with such a stable water temp, even in hot weather and inspired driving it rarely goes over 90. It can also sit on idle in 30 degrees C, and it will take a loooong time for the fan to kick in. That's one helluva powerful waterpump!

We've owned three different E420's (124.034) and all of them ran much, much cooler than the 500E's, even though the 420's had old/original water pumps and one of the 500's has a new pump, all with new t-stats. I'm still not sure why there is such a big difference between the two in high ambient (summer) temps.

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Hi,

Yes if Id have known about front seal I would have done it at the same time. Right now I dont have the time to start the job again!

My car does less than 1500 miles per annum so im hoping it wont start leaking!

p.s. I had a similar issues with my W124 300TE 3.4AMG... again water pump has solved the issue and again I could see nothing wrong with the old one..

The next job for the 500E is a minor power steering leak... again been there ever since I had the car.. changed most of the pipes yet it still has a slow leak... Also the level in the reservoir does strange things.. sometimes its low and then mysteriously gets back up to level by itself after running!

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

With the colder weather now here in Houston (daytime temps in 70-75F range) I am seeing a HUGE difference in running temps on my E500. It is rare for the E500 to get beyond 90-92C now, whereas in summertime (90-100F ambient temps) 100C and even 105C in heavy traffic/high loads was normal. The replacement of the radiator with a new Nissens unit early in the summer made NO difference as to running temps of the car.

Bottom line is that at ambient temps above 85F, the E500E running temps seem to spike to the 100C range, sometimes beyond.

My cooler-running (even in summer) 560SEC and 560SEL are now hard-pressed to even hit the 85-87C mark on the temp gauge.....

The next job for the 500E is a minor power steering leak... again been there ever since I had the car.. changed most of the pipes yet it still has a slow leak... Also the level in the reservoir does strange things.. sometimes its low and then mysteriously gets back up to level by itself after running!

The most common issue with the power steering system is a leaky short-hose between the reservoir and the tandem pump. Less common, but happens, is a leak in the PS portion of the tandem pump itself, requiring pump removal and re-seal. There is a detailed HOW-TO article in the archives on how to remove and re-seal the entire pump.

The short hose is a much less involved job. If that is the problem, I'd recommend that you buy a new gasket that fits in between the base of the reservoir and the platform it sits on. You will need a female Torx socket to remove the reservoir bolts, which is not an item that many mechanics have. No idea why MB used these fasteners for this application !!

Does your PS fluid level always go back up to the same level? I.E. are you actually losing fluid from the system? How much does the level fluctuate? I'm wondering if you just have air in the system, and that is causing the fluid level to fluctuate a bit.

Also, be sure to check your steering box output shaft seal (pitman arm) as this is also a common leak point for the steering system. Mine had a slight leak so I decided to change it out. Be sure to also check the low and high-pressure PS hoses from the pump to the steering box. One of these hoses, which runs along the frame rail underneath a heat shield, is a REAL b*%ch to replace. So much so that I didn't bother to do it because it wasn't leaking, whereas I replaced all other hoses in the system. None of them are particularly easy to replace in the E500E steering system....

Let us know what you find.

Cheers,
Gerry

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Thanks,

I had a good go at the PAS leak some time back, changed most of the pipes apart from that long one as you say, I couldnt get to it... Will have to reinvestigate sometime soon.

The leak is slow and has been there since I have owned the car... a small top up every few months is all it needs.

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

I will say prayer for you that it isn't the long inaccessible hose....90% of the time it seems to be that short hose south of the reservoir though.

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Any update on the PS system leak? Hoping it is/was just the short hose from the reservoir to the pump. Let us know.....

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Hi,

I havent had a chance to look properly, nothing visible apart from drops on the floor! Im thinking to just order a used pump and swap it as I know these are known to leak... That way ill change the hose and the pump and hopefully cure it.

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

It's MUCH more likely that the hose is leaking, as opposed to the pump. It's much simpler/easier to replace just the hose too.

You can glean the process from this post. Basically you just have to remove the reservoir, so need a couple of special tools (female torx and a large (10mm IIRC) Allen socket. And a metal sealing ring and new paper gasket for the base of the reservoir. And a new length of hose too. I put four clamps on the new hose (instead of the specified two clamps) and cut it about 1 cm longer than the stock length. This would be an easy fix to do in a couple of hours, and a good time to change out the SLS juice too.

Cheers,
Gerry

 

[jaymanek]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Wow thanks... awesome pictures... I have just ordered the parts so will tackle it when I have a free hour or two.

 

[gerryvz]

Re: 500E Running Hot - Water Pump, Viscous FanNow Solved

Yeah, give yourself about 3-4 hours to do the job. Have a full liter of PS fluid on hand, two liters is better (one for reserve is always good). I replaced the threaded metal flange that screwed into the base where the reservoir sits and extends down into the short hose; you don't need to do this, but DEFINITELY you must replace the crush washer on that piece.

The MB gasket is very expensive for what it is; aftermarket gaskets are a fraction of the price but don't include the rubber bead around the edge of the gasket. I'd recommend you save yourself GBP 15 and go with the aftermarket version. I also ordered new female Torx screws for the base of the reservoir; you shouldn't need to do this although the heads can get a bit stripped out if you're not careful upon removal.

Recommend you go with more clamps "while you're in there" as they are cheap and can help better secure the hose so that it doesn't leak.

Also note that the tandem pump does both suspension (rear portion) and power steering (front portion), so not a bad idea to clean the pump and surrounding area off before you start the job, and drive the car, to be sure that the pump itself (or the S high-pressure hose) is not leaking. 90% of the time, though, it's the short hose.

Cheers,
Gerry

 

[jaymanek]

Hi,

Well I tackled the short power steering hose job today... all went smoothly.

There was a lot of crud under the reservoir area... Im not sure if that was my leak or not but at least its one more suspect down!

The old pipe was covered in black stuff but didnt look to be damaged in any way.

Ill have to keep an eye on it now... Will report back.

 

[gerryvz]

Hi,

Well I tackled the short power steering hose job today... all went smoothly.

There was a lot of crud under the reservoir area... Im not sure if that was my leak or not but at least its one more suspect down!

The old pipe was covered in black stuff but didnt look to be damaged in any way.

Ill have to keep an eye on it now... Will report back.

Awesome !