Symptoms of overheat diesel? 87 300D - Page 2 - PeachParts Mercedes-Benz Forum

ILUVMILS · #16 07-31-2008, 12:20 PM

I had an issue like this recently on my 94' E320. Driving along with the A/C on was no problem. As soon as I got into stop-and-go situations, the coolant temperature would slowly begin to rise. The first thing I checked was the auxiliary fan. Guess what? It didn't come on until the engine reached approx. 100C, which happens to be the second stage of fan activation. The first stage (lower fan speed), which is activated by A/C pressure, never came on.

To make a long story short, the problem turned out to be a slight dis-charge of the A/C system. I added six ounces of R134, and presto! The high-side A/C pressure increased just enough to activate the stage 1 fan and now I can leave the car idling indefinitely on a 95 degree day, and the engine temperature never goes above 93C, even after several hours.

a2t · #17 08-01-2008, 12:21 AM

OK I drove today and couldnt really get coolant temps over 100C. It was kinda cloudy out and not as hot as its been. I drove it pretty hard tonight in light rain and when I got home I think it was reading 95C coolant. Popped the hood and metal fan could spin by hand easily in both directions.

Engine coolant was 95C. Does that tell me anything?

Cervan · #18 08-01-2008, 02:07 AM

Quote:

Originally Posted by a2t

OK I drove today and couldnt really get coolant temps over 100C. It was kinda cloudy out and not as hot as its been. I drove it pretty hard tonight in light rain and when I got home I think it was reading 95C coolant. Popped the hood and metal fan could spin by hand easily in both directions.

Engine coolant was 95C. Does that tell me anything?

if you have no mixing of fluids and your not loosing any fluids, its safe to say you didnt blow the headgasket. my 240d used to hover around 100C in the summertime, then i cleaned out the radiator and it was down to normal after that, you might want to try that too.

a2t · #19 08-02-2008, 10:51 PM

what does it mean if metal fan is easy to spin by hand after shut off at 95C?

Cervan · #20 08-03-2008, 01:02 AM

means you should install a manual one

TMAllison · #21 08-03-2008, 12:58 PM

Quote:

Originally Posted by a2t

OK I drove today and couldnt really get coolant temps over 100C. It was kinda cloudy out and not as hot as its been. I drove it pretty hard tonight in light rain and when I got home I think it was reading 95C coolant. Popped the hood and metal fan could spin by hand easily in both directions.

Engine coolant was 95C. Does that tell me anything?

Next time its at 95 or 100C leave it running with AC on and check to see if your aux fan works....it ought to be running at those temps.

BrianCostello · #22 08-03-2008, 03:38 PM

Quote:

Originally Posted by a2t

Popped the hood and metal fan could spin by hand easily in both directions.
Does that tell me anything?

Yes you need to replace the fan clutch and blade assembly.

The proper replacment for the 1987 300D is VERY expensive. Thanks to tis site I just ordered the cheaper version.

order the following:

Fan Clutch : 606-200-01-22

Fan Blade: 606-200-01-23

Like I said I just ordered mine, going to install next week.

Best of Luck

Brian

Bio300TDTdriver · #23 08-03-2008, 06:16 PM

Quote:

Originally Posted by a2t

what does it mean if metal fan is easy to spin by hand after shut off at 95C?

Well it means the fan clutch is not engaging. Is it not engaging because the viscous fluid has leaked out or because the air reaching the spring is not hot enough to engage the fan? If you replace the fan and clutch with a new one and the air reaching it from the radiator is not hot enough to make it engage, it still won't engage.

I replaced my fan and clutch and it did not cure the problem. It looks like I need to do a citric flush.

a2t · #24 08-04-2008, 05:31 PM

Thanks. What make/model are those 606 part numbers from? Cant remember.

The engine is really hot, I cant believe no hot air is reaching fan. It just hit 110C. I stopped motor and could spin fan freely by hand, absolutely zero resistance. It should see some resistance right?? Even if not seeing scorching hot air, it shouldnt spin around 10 times before stopping in this heat.

a2t · #25 08-20-2008, 09:10 PM

So I posted a while back on overheat issue on my 87 300d. Gets hot while not moving, moving slow, esp on hot days after high speed cruising.

A few of you directed me to fan clutch. So I tested fan clutch, at 105C stopped engine and can freely spin the metal fan by hand. It spins with engine on, but its definitely free to spin by hand with engine hot.

Ive heard of the cardboard test on BMWs where you push piece of cardboard against fan with engine running hot, and if you are able to stop fan from spinning the clutch is toast.

Is this worth trying, or has the diagnosis already come back for me?

If it is fan clutch, what are most economical options here?

Thanks for all help!

Jeremy5848 · #26 08-21-2008, 12:13 AM

Quote:

Originally Posted by a2t

Thanks. What make/model are those 606 part numbers from? Cant remember. . .

They are from an OM606 engine, which was used in the 1995 E300D (W124) and the '96-97 E300D (W210). Possibly also the '98-99 E300D with the Turbo 606.

Jeremy

Jeremy5848 · #27 08-21-2008, 12:14 AM

Quote:

Originally Posted by a2t

Thanks. What make/model are those 606 part numbers from? Cant remember. . .

They are from an OM606 engine, which was used in the 1995 E300D (W124) and the '96-97 E300D (W210). Possibly also the '98-99 E300D with the Turbo 606. I put the 606 fan and clutch on my 603; don't notice any difference but it hasn't been very hot here and I have a good cooling system anyway.

Jeremy