Greetings:
my new to me 87 wagon runs warmer than it should. First I live in Evergreen CO. 7800ft elevation. Around town and in Denver the car runs rock steady at 85 degrees, however, climbing I-70 west of Denver 6% plus grade 5300ft-7900ft at 70-80 mph a/c on temperature rises at the top of the climb to 115c with outside temps 40-55 degrees, I am worried that in warmer temps the car will over heat. car has 144k well maintained, no head issues, no coolant loss,

So far I have accomplished the following:

1) New nissan radiator and MB antifreeze 50/50
2) new clutch and fan
3) new thermostat
4) new temp guage sender
5) new electric fan temp sender
(the electric fan is working)

The around town driving as I said stays right between 80-85, the long climb up to Evergreen is about 10 miles, is there anything I am missing any other suggestions or is it normal????
Thanks
Ron

Air in the coolant system?

Is the A/C condensor plugged up?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Thanks for the reply, no air in the system and the air cond seems to blow very cold, so I am assuming that the condensor is working, could you expand on the condensor issue?
Thanks
Ron

I figure if the condensor if plugged up (dead bugs and the like) then it'd hamper flow to the rad. I'll assume then it'd been burped properly.

It could be you do have bad, new parts too. I've had them in the past.

What about the H2O pump? The E-fan original, aftermarket, or replaced?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Just an idea / This may not even apply to you.
I had an 87 wagon (great car btw) and busted the radiator after driving over a branch that put a hole in it.

In attempt to save some money I went with a copper radiator instead of the aluminum one that it came with.
The car had a very hard time staying cool. I eventually got a salvage aluminum radiator.

Radiator is OEM Nissan, Thanks

Have you tried this same grade w/ the A/C off also? If so, what are the results...

Could be you have a bad clutch, despite it being replaced . It should lock at the preset temp.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

The water pump seems to be moving coolant just fine, the electric fan works as it should comes on with A/C or 105c, don't know if its original or not?

Might be your temp gauge. Get a hand held lazer temp guage, pull over and take reading from the engine. It will give you the right temp.

BTW ever sell your other 300TD?


Andy

__________________
83 300D 169K (Mine)
86 F250 4X4 6.9 (Mine)
05 VW Passat TDI (Wife's)

The 85 sold right away, could have sold it about ten times, nice car I miss it already.

Forget the above! They try, but there are some basic issues here that you should consider!

#1. Your car is almost 19 years old. If the radiator has not been replaced since 1987, I strongly recommend that you confirm that it circulates coolant as it was new, or replace it!

#2. Thermostats require periodic replacement. 5 to 8 years may be considered an active life span for effectively regulating engine temperatures.

#3. Fan clutch........or actually they are silicon filled and respond to predetermine temps that actuate the fan for pulling air through the radiator. They dont last forever and when worn do not pull air through the radiator as the designers planned. I just replaced mine!

#4. Auxiliary electric radiator fan. Actuated from a thermo switch, @ 105c, can fail to work if either the thermo switch is faulty, or the elect fan is faulty.

Figure that any of these parts become suspect automatically after 150K, or sooner.

By the sounds of you description, you are playing Russian roulette with you OM603 as these engine are particularly susceptible to overheat situations that usually result in $3K to $4k for repairs, as a result from overheating the engine that WILL catastrophically crack the aluminum head.

One exception, if unless the head has been replaced with the MB redesigned OM603 aluminum heads ...#17 thru #22, you need to seriously make sure your cooling system is 100%..............these OM603's in particular, the same as you have described here.............get with it, or it will let you down......Many many posts, threads here on this topic...............read.........BB

BusyBenz:
Please read my initial post regarding this issue, all of the items you mention have been recently(this week)
replaced, Russian Roulette, hardly, I maintain all of my cars way beyond even the most conservative recommendations, Thanks though.
Ron

I've thought about this over the past several hours and am pondering the following:

At 7800 feet, the ALDA should have significantly reduced available fuel to the engine. There is insufficient air at this altitude to handle the typical fuel at sea level.

So, with reduced fuel and reduced power the engine should have an easier situation then running the same 6% grade at sea level.

What is troubling me, and it might just be the fact that its a 124, is the capability of going 80 mph on this grade at this altitude. I am quite certain that the W126 with the 603 engine cannot achieve and hold 80 mph on a 6% grade at an altitude of 1000 feet. Now the relatively aerodynamic body of the W124 may allow this, but, I'm not so certain, especially at that altitude.

When going 80 mph up that hill, was that maximum available power?

Do you see any smoke while climbing the hill?

It's an interesting situation. I'm inclined to believe the gauge. I think you have covered every other possible piece of hardware.

I wish to caution you on pushing the temperature above 110°C. With the propensity for these heads to crack, you might consider slowing the vehicle down to 50 mph and thereby cut the boost significantly. The temperature will stabilize at a minumum, and, hopefully begin to drop. The gauge has a red zone at 120°C. Don't believe it.

Sorry, I didn't read closely enough, but I cannot stress enough just how sensitive these heads are prone to crack. Running 115C would curdle my insides. I would shut mine down if it did not effectively cool beyond 105-110C!

Beyond the cooling system components I mentioned, there are few recommendations to consider. Engine timing that may be off, as a result of chain stretch, are only a few possibilities for excessive temps. Usually it has more to do with worn, or restricted, cooling system components!

Sometimes replacement parts are faulty too!

Thanks Brian,
The car came from Texas orginally, and when I first brought it to this altitude it performed badly, after adjusting the ALDA per GSXRs (Daves)recommendation the car produces very little smoke and performs excellent, beleive it or not at 80mph the car seems like it is hardly working even at this high elevation, it will easly accelerate under these conditions, clearly this is NOT the case(working easy) in light of the indicated temps,but the car has lots of seemless power, fuel consumption 27 plus miles per gallon, really runs smooth.

What does concern me is the possibility of head or head gasket failure related to overheating, I plan to run the car up the hill at 65 mph to see if it stays cool, however, at 70-80 the engine really feels in a sweet spot. Thanks again
Ron