1987 300E coolant temperature / fan clutch
 

Hello

I have a 1987 300E since 2001.

I have noticed when the vehicle sits in stop and go traffic or if I leave the car running when I get home for 10 minutes or so the temperature slowly creeps up and eventually the electric fan comes on at 105C, and it seems to stay on, or go off briefly and come back on.

The radiator and thermostat are in good shape.

I am thinking the fan clutch might be a bit worn.

The fan clutch does engage and spin however I was told that it didn't seem to spin that fast. I was told they tend to roar a bit. My fan clutch plastic fan version has 11? blades. I see that the replacement is 9 blades.

Its behavior has been the same since I have owned it (18 years).

I recall reading threads over the years that other owners mentioned that the temp creeps up in stop and go traffic.

There is a youtube video that shows the safe way to test it.

When the car is cold by had the fan will spin for 1 to 1-1/2 revolutions. When hot and the engine turned off the fan continues to spin for a while. The video mentions it should come to a stop much sooner.

Any ideas how to be certain my fan clutch isn't working at its peak.

I'd rather not have it changed out unless I am certain it is bad.

???

Thanks

You've already diagnosed the clutch as bad. Freewheeling on shutdown is a classic symptom of a bad clutch, even when ice cold it shouldn't freewheel. A bad clutch won't transmit power to the fan to actively draw air through the radiator. If the coolant temp were getting that high, you should definitely hear it roaring a bit when the engine is revved. While you're doing maintenance, wash out the A/C condenser, and wash between the condenser and the radiator. You'd be surprised the crap that builds up in there.

The car sat overnight, this morning the temperature was 59F or 15C.

When I started the car the fan clutch fan was spinning.

Wanted to confirm that it should NOT spin at this temperature?

Thanks?

The fan always spins, but when it's not engaged it's slipping and not a full speed.

The fan should always be spinning, even if the clutch is not engaged. The fluid in it creates some drag so that it spins, but slips. When working properly, the fluid increases the drag in the clutch, reducing slippage, so that the fan runs faster and draws more air. Freewheeling at shutdown is a sure sign the clutch is garage and has been junk for a long time. A good clutch will stop just about immediately or maybe coast a fraction of a rotation. Replace it. A fan clutch is cheaper and easier than a head gasket.

Just add some silicone oil to it. If you want, I have a heavy duty clutch that I used to run in the summer before upgrading to the electric fan. I think I put in 2500 cst silicone. When it engages you definitely hear it. Think of being next to an 18 wheeler when it takes off from a stop. The good thing is that once it engages, you're engine is cooled to temp within a minute or 2.

Our forum host offers URO Fan Clutch 103 200 0422 for the 1986-1993 300E, which has nothing but 5-star reviews on one of the big retail sites. https://www.pelicanparts.com/More_Info/UR1032000422.htm?pn=UR-103-200-0422&bt=Y&fs=0&SVSVSI=3303

Bought this exact fan clutch and it failed after a little over a year and 15k miles.

Hi Christuna, sorry to hear that, we haven't had any issues with this clutch but we'll have engineering check it out anyway. Would you happen to still have it? Please PM us your purchase details (date, retailer, order number) and we'll be happy to send you a warranty replacement.

I have not bought the Uro fan clutch, but I have bought other Uro brand parts and my personal experience is that the majority of the parts that are in high stress/load locations fail prematurely, usually within a few months. I think the OP would be better off getting a used OEM brand clutch instead of a new Uro brand.

I purchased the URO fan clutch it is arriving tomorrow. I see that there is a Behr one available for $90.

The parts arrived today.

I ordered a URO fan clutch and a FEBI 9 blade fan as my fan was the older 11 blade type.

I do most of my own work however was thinking of having a Mercedes mechanic I know do this job. Should I proceed with the URO fan clutch or purchase a Behr or other. Even if Uro back up the part the labor is costly.

????

Seeing that you could do that job yourself, I would get a better quality fan clutch and skip the cost of having a mechanic do it. On my 201, I'm able to remove and install a fan clutch without taking or emptying out the radiator. The m103 in the 201 is probably the most restricted to work on front engine bay wise.

I did a bit of research on doing this job. The part I was not confident about was how to hold the fan clutch when removing and installing the fan clutch. I see that there is a tool that is available, it is a rod with a bent end. the bent end of the rod goes into a hole in the water pump pulley? and the rod gets inset into a slot in the water pump housing. I could buy the rod and mess with it all but am looking to have some other work done at the same time and might only get charged and hour or less for the fan clutch job so was thinking of just going for it.

Long 3mm or 4mm hex key works fine. However, do whatever you feel is your best option, but use a better quality clutch. For critical parts always use the best quality. Something like an interior trim piece or something that is of no significant importance if it fails, you could try saving a few dollars by going with the unpopular brand. Just my 2 cents. Good luck.

I would have to go and look for it if it hasn't ended up in the trash yet.

that was months ago and I bought it from an ebay seller and have since replaced it by a BEHR unit $85 was the damage iirc.

Don't want anything failing on me when i'm on a trip in Canada

I actually use a bent aluminum rod to lock the bearing bracket.

BEHR stuff is quality. Their radiators necks are reinforced and fan clutch slide valves aren't held together by glue

So the URO fan clutch just arrived last night and after reading some posts here I am thinking of purchasing something better.

Here are my choices see attached images. I am leaning toward the Behr.

Suggestions?

Turn the fan by hand when the engine is cold. Then, again when the temp is over 100C. It should be quite stiffer. It sounds like your fan clutch is not functioning properly. Some have added silicone fluid that you can buy from hobby shops, it think, but if the seal is bad it will likely leak out very quickly.

Also, if the fan clutch is good you should definitely hear "fan roar" if you rev then engine to 2000 or more. If you don't hear fan roar at over 100C the clutch is bad.

When cold the fan should keep spinning a bit after engine shutdown. At over 100C when the clutch is fully engaged it should stop quickly.

While idling the mechanical fan doesn't flow much air, even if the clutch is fully tightened, which is why these cars have auxiliary electric fan(s). (My 190E 2.6 has two that are smaller diameter than the single electric fan on your 300E.)

Running the A/C in low speed stop and go traffic actually aids cooling because the electric fan(s) engage at low speed from a A/C system pressure switch, and temp may not reach 105C when they engage at high speed.

In hot weather stop and go traffic once the temp get to 105C and the electrics engage I can actually see the temp gage needle moving down to when they shut off at 100C. Then the temp creeps up again fairly quickly and they engage again, so the "duty cycle is probably close to 50 percent.

That's typically how modern engine cooling systems work, however, especially on FWD vehicles with "sidewinder" drive trains, there is no mechanical fan... just one or two electrics. The other issue is that most modern cars don't have temp gages, only an overheat light, so most owners have no idea what coolant temp actually is and may even be oblivious to failed electric fans until the "engine temp" light illuminates or coolant is expelled and steam rises from the engine compartment.

Duke

Folks might be surprised to know that many of our parts come off the same production lines as some of the "big" brands - including B***.

We sell almost 150 of these clutches annually, and only two were returned as "defective" (which often isn't always the case, sometimes someone wants to return a part and just says that) in the last year. The 5-star reviews on A***** for this clutch are also a good indicator.

Will PM you, we'll make it right.

For what its worth, no one on my Volvo forum uses URO parts either. I DO have URO trunk struts on my 1999 C70 Cabrio, they have worked just fine for years. But I'd not ever use URO for anything even remotely critical. I also understand ones' need to economize.

Appreciate the support from URO.

Does this part (1032000422U) come off the same production line as B***?

If the fan clutch fails prematurely will you cover the cost of labor?

The cost difference compared to the B*** is $35, I am thinking or returning the URO and getting the B***.

After I drove to work today I turned off the car, the coolant temp was in the low 90s C. I spun the fan by hand and it spins at the exact rate as when cold, (about 1-1/2 turns before it comes to a stop)

So it is confirmed bad.

No I just need to decide if I should return the URO fan clutch I just bought and get a BEHR or keep the URO.

Naturally we don't have access to contracts between our competitors and the manufacturing firms they buy from, but at trade shows we routinely view competitor's products and recognize that they're the same as ours. There are only so many manufacturing companies producing expansion tanks, or relays, etc. With laser logo application or swappable inserts in injection molds, it's easy for a manufacturing company to private label the same item for several brands.

Looking at the photos, it appears that the B*** fan clutch isn't the same as ours.

Officially our 2-year, unlimited mileage warranty doesn't cover labor or incidental expenses, but we do consider a variety of factors when evaluating warranty requests. Sometimes if a customer no longer needs a warranty replacement item (they already replaced it), we're happy to substitute other URO item(s) of similar value that they can use, as reimbursement.

It's a pretty easy job, but you do need 2 tools to keep it easy. The 1st is something to hold the clutch which Ismalley already gave you a good option. I used a metal rod (about 1/4" in diameter) that I bent the end. The other is an Allen wrench or socket to turn the fan nut. The clearance between the fan and radiator is minimal. I'm not sure, but I think it was an 8mm Allen.

The fan clutch doesn't really tighten until 100C. My experience is that it acts like and on/off switch rather than tightening slowly as the temp rises.

Let it idle and before temp reaches 100C rev the engine to about 2000-2500 and "feel" the air flow and listen for fan roar. Then let it continue to idle until it's over 100C, but less than 105 when the electric fan engages. You should feel more air flow at 2000-2500 and hear plenty of fan roar.

Shut off the engine and check how much force it takes to turn the fan by hand. It should be much greater than when cold.

Failure of either of the above indicates an inoperative fan clutch.

Duke

just had the URO fan clutch installed
 

HI

It took almost two years, I finally had the URO fan clutch installed today.

Upon startup and pulling out of the shops parking lot I could hear the fan roar a bit, and the car was cold.

I'll update this thread with updates as necessary.

^ Our fan clutches have traditionally been are on the "aggressive" side of the temp/engagement spectrum, which is safer than engaging at too high a temp. Engineering has been slowly working to fine-tune the engagement temp closer to OE, but it's been small running changes in production, and nothing drastic that anyone will probably notice.