'95 C36 - Running Hot

[Bob996]

Hey Guys,

I could really use some help, I cannot find another site that offers the wealth of knowledge you guys offer up! I'm aware this forum is dedicated to the 500e; PLEASE feel free to delete my question for posting here if need be.

To the point, I am a little concerned about the way my C36 has been acting lately, the car seems to be running hot. I honestly have trouble understanding the correct operating temp for the M104 or M119 for that matter, it seems to hover around 95-100c in traffic before the aux fans kick on but within minutes the temp rises back to 100-102c prior to the fans coming on once again. My 500 never ran like this, I compared the two. I noticed the other day that the coolant reservoir was at 3/4, I had it flushed a few weeks back. I put around 800-1000 miles on the car since. I refilled it a week ago; I do not see any visible leak. A pressure test was performed at the time of the flush that came back with positive results. I know the radiator and fan clutch is original. I was thinking one of these parts might be the culprit, is it a good idea to replace these as preventive maintenance considering the age? The water pump was replaced at 123k miles, the gasket was done back in 10/98 when it has 53k miles, it now has 139k. Cap is almost brand new. I cannot find any type of contamination in the coolant or oil. This issue has me stumped. The car is my daily right now, I need to know that everything is operating properly.

Any advice would be very much appreciated! Thanks again for all the help with selling my car and the assistance when I reached out!!

Cheers,

-Bob

 

[nocfn]

Air bubbles in your system?

 

[ccrelan]

Bob- the 3.6 engines tend to run hot. With that said, if the fan clutch is original it would probably be a good idea to change out. Some people do a test on the fan clutch with a rolled up newspaper in the way of the fan blade. Redline water wetter is a good product as well.

 

[bing]

Those temperatures are not uncommon if living in high ambient temp area, sitting in traffic and A/C on . How hot is it outside when you see this ? Certainly the visco fan clutch is suspect if indeed original , again very common failure and overlooked. The good news is your aux fans are operating as they should.

The reduction in coolant is a worry though since you've recently flushed it. Perhaps it wasn't topped up correctly after this? I'd keep eye on this after topping up . You shouldn't have to top up that soon , if at all !

 

[samiam44]

Is this running hot recent? Ie has it been doing it for sometime.

Two comments- yes, I think that fan clutches are a big factor. Secondly, not sure what water pump you are running? But sometimes the aftermarkets don't use a factory style impeller or don't press it on to the right depth. Wrong size impeller will do it too.. All that- I ussually use MB water pumps.

Third, Pull the radiator and clean the fins by back flushing at the carwash. I use compressed air to back blow and clean the condensor coils.

But to answer your question, no they should not run hot.

My 500e ran hotish and I replaced the water pump, new fan clutch and cleaned the coils ... now it runs 85-95c. Still the original radiator.

Michael

 

[gsxr]

Ditto what everyone else said above. In addition, if the radiator is really 20 years old... yes, I would consider replacing it. The fan clutch can be tested via the "roar test" described in the Wiki, however keep in mind that this requires warm ambient temperatures (80-90F+) in addition to warm engine temps (95C+), and a failed test does not absolutely confirm a defective clutch... any airflow blockage in front of the clutch (or, a cool spot in the radiator) will affect clutch engagement.

 

[Bob996]

Thanks guys, I ordered a new radiator, fan clutch, and what looks to be an updated fan w/ 9 blades. I hope these parts will produce some results. Two people told me their water pump developed a leak immediately after flushing with the updated blue/greenish color coolant. The car is going to get a thorough look-over.

The help is appreciated for someone that just sold their car on the site!!

 

[gsxr]

Interesting about the new blue coolant (G-48)... I would stick with the old stuff, it is still available from almost any local auto parts store as Zerex G-05. It is identical to the gold MB dealer antifreeze used for the past few decades.

 

[Klink]

Two people told me their water pump developed a leak immediately after flushing with the updated blue/greenish color coolant. The car is going to get a thorough look-over.

Interesting about the new blue coolant (G-48)... I would stick with the old stuff, it is still available from almost any local auto parts store as Zerex G-05. It is identical to the gold MB dealer antifreeze used for the past few decades.

I haven't heard of that, but yep, the Zerex is readily available all day long. Now, FWIW, coolant pumps ocasionally do develop leaks right after a coolant change. They always have. So does every other fluid containing system...

 

[SG-Motorsports]

Strange that nobody has mentioned the thermostat yet, but they are really common failures on M104's. That would be the first thing I would check, they are cheap and easy.

I wouldn't worry too much about air in the system, the m104 doesn't have many air pockets to get you in trouble, once run at 2500 rpm at temp for more than 5 minutes all air should be gone. They're not hard to burp at all.

 

[Klink]

Strange that nobody has mentioned the thermostat yet, but they are really common failures on M104's. That would be the first thing I would check, they are cheap and easy.

I wouldn't worry too much about air in the system, the m104 doesn't have many air pockets to get you in trouble, once run at 2500 rpm at temp for more than 5 minutes all air should be gone. They're not hard to burp at all.

LOL! I hadn't noticed that nobody mentioned it. So true! The thermostat may actually be the single most common component failure on the M104...

 

[gsxr]

LOL! I hadn't noticed that nobody mentioned it. So true! The thermostat may actually be the single most common component failure on the M104...

Me neither. Bad Dave! Yes, t-stat is #1 on the list after a pressure/leak test.

 

[Klink]

Me neither. Bad Dave! Yes, t-stat is #1 on the list after a pressure/leak test.

I know! My dumbass hat was cinched up tight on this one, too. Thanks Steve!

 

[Bob996]

Strange that nobody has mentioned the thermostat yet, but they are really common failures on M104's. That would be the first thing I would check, they are cheap and easy.

I wouldn't worry too much about air in the system, the m104 doesn't have many air pockets to get you in trouble, once run at 2500 rpm at temp for more than 5 minutes all air should be gone. They're not hard to burp at all.

Thanks for the recommendation, I replaced this part earlier today and the car still gets up there. It never hurts to change a thermostat as preventive maintenance.

I'm pretty sure I know which part is not operating correctly now, I read up quite a bit on the fan clutch and how it should perform. It looks like there are a few ways to test it, the one I tried today was waiting for the car to hit a 100c and taking two pieces of newspaper and firmly applying it to the fan. When I did this the fan stopped almost immediately and now when I turn the car off it spins freely around 15-20 times before it stops.

Would you guys agree this clutch sounds like the culprit part? There is hardly any room to get in there to replace this part! Has anyone ever replaced the fan clutch on a M104? If so, please chime in with a diy and it would be very much appreciated! I found two tools online that look as though they make this job much easier. This is what I will be tackling next week.

I hope everyone has a good holiday!

 

[Bob996]

I plan on ordering the parts tonight, I was hoping someone could take a look at the list of parts. I decided it would probably be in my best interest to swap out the bearing too, and a few other parts. I need to know if I am missing something or if there is a part on here that should not require replacement.

Your feedback would be appreciated:

104-200-01-22
Fan Clutch

104-200-20-28
Bearing Bracket - Fan / Fan Clutch

103-200-04-23
Fan Blade

104-205-02-10
Fan Clutch Pulley

104-200-08-70
Drive Belt Tensioner - Without Pulley

119-200-14-70
Drive Belt Tensioner Pulley

601-200-10-70
Drive Belt Pulley on Fan Clutch Bearing Bracket (Grooved) 64 mm O.D.

Thank you!!!

 

[gsxr]

Be careful what brands you purchase. For example, on the bearing bracket, the only quality item available is the genuine MB part from the dealer...

 

[Bob996]

Be careful what brands you purchase. For example, on the bearing bracket, the only quality item available is the genuine MB part from the dealer...

I hear you Dave, the fan clutch is Behr and the bearing bracket is made by Febi Bilstein. Do you happen to know the manfacturer of the dealer part? Does the drive belt tensioner (part# 104-200-08-70) require replacement? I believe this part should have been changed when the new water pump was installed not too long ago but it was not. My knowledge on the cooling system is not the best!!

I want to make sure I am ordering all the right parts. Get this stuff knocked out and then I can tackle the A/C.

Thanks.

 

[gsxr]

The OE bearing bracket has no obvious brand names on it, but is marked "BWF" on the back side. AFAIK it is not available aftermarket, you have to get it from a dealer. One of the discount dealers should have it for 20-20% off MSRP. Don't use the Febi bracket... the one on my car and it failed in 40kmi, despite being clearly marked "Made in Germany". The Febi was installed by a shop courtesy of the PO, I replaced it with a new OE/dealer part.

I don't think the tensioner is a common failure... probably does not need to be replaced proactively. Ditto for the pulleys and fan blade. Some Behr stuff is being made in China now, and I'm not certain if the OEM is Behr or Sachs for the fan clutch. I prefer Sachs over Behr but they tend to cost a bit more (probably because Sachs hasn't yet moved production to China?).

 

[Bob996]

I'm glad you posted back about this Dave, thank you. I think it would be wise to hold off on the purchase of these parts for right now. Sachs and this other manufacturer you mentioned do not flood the market with their parts and keep the product within the dealership, I cannot blame them in this day and age. I know someone at the dealership, but he can only offer me 10-15% off parts at best. My 996 was fully serviced last week, I plan to drive the car for the next week or two and this will give me the time to find the proper parts.

It's a shame that some of the big German players switched their production to China, the market has become very competitive for parts and there are many cheap alternatives selling at 50% of the price. I struggled to find a genuine Bosch MAF for this car recently. The German beer too, I was drinking a Becks out on my friends deck the other day and realized they now bottle in Missouri for the US production. Nothing beats a Franizkaner in my opinion! The car needs to be good by the end of the month, I hope to at least get the parts ordered sometime this week, if anyone happens to know an online retailer that stocks Sach and the other mfg. please advise.

Cheers,

-Bob

 

[gsxr]

For discount dealer parts, try Lionel at MB Gainesville, or Tom Hanson at the MB Classic Center (search forum for contact info on both of them). Pretty sure both will do 20-25% off list price, possibly free shipping as well.

 

[samiam44]

I would worry about the pulley without a bearing. But I agree with Dave on parts here.. try Tom Hanson (west coast) or call and talk with Lionel @MB Gainesville. Tell them you are a member of this list and get free shipping and deep discount.

Nothing throws off troubleshoot worse than a new defective part. Aftermarket fan cluches have a bad habit of coming apart and then you need a new radiator/fan/clutch and have a heck of a mess.

Michael

 

[Bob996]

I'm glad to post back with positive results after replacing the bearing and fan clutch. The car now hovers around 88-90c in stop and go traffic, I have not seen it surpass this temp and it was quite humid in VA today.

Thanks again, I appreciate all the help and guidance!!