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Cooling problem
300e 2.8 M104 engine.
The temperature stay at 100-105 C when ambient temp is over 85 F. Even if I am driving on the Hwy at 70Mph it does not go lower than 100 C.It is a permanent cicle of the auxiliary fan. But if I am in trafic and the engine is ideling the car cools down to 87 C in about 5 Min. I have done the folowing: New fan clucth ,new radiator, new termostat, flush the coolant with genuine MB fluid. Also I have changed one of the auxiliary fan that was bad. The aux fans work fine. They start when the A/C is on, in first stage and at 105 they go in second stage . I don't Know wat coud be. Most of the people on this forum claim that a soon as the car is driven at hwy speeds the engine should cool down.Mine is the other way.....!!!!!!
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New Addition to the family 2013 Passat TDI 5Miles 2004 E500 4MATIC Wagon 95k 1996 E300 Diesel 173k Sold 1993 300E 2.8 230k Sold 1994 E320 White Wagon 373K Sold Still dreaming about ....500E Radu Negru |
#2
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Possibly there is a problem with the temperature gauge, maybe it is inaccurate?
Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#3
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if the car is idling (like in traffic) its not building much heat in comparison to driving at freeway speeds.
conversely, while idling in traffic there is little airflow through the radiator while there is plenty at freeway speeds. i surmise that there must be some kind of blockage thats preventing air from flowing freely through your radiator at high speed, and that the coolant capacity is enough to cool the engine when the engine isnt producing much heat. leaves, insects, other debris could be in the fins of the radiator or the AC condensor, preventing airflow. i say check there first. clean out as nec, and observe for any changes in temps.
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'O=00=O' bmw 2002. long live the legend |
#4
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Replace the pressure cap, too!
Check for a soft lower radiator hose -- if it's mushy, it can collapse at high engine speed, reducing cooling capacity. This usually only happens with a non-pressurized cooling system (bad pressure cap). If you also get some coolant spill or brief boiling noise when you shut off hot, for sure it's a bad pressure cap. Otherwise, it's time to check for coolant flow (difficult on this car) -- you may need to use an infared thermometer to check radiator temperature, it may be plugged from residual crud from the cooling system (bummer!). Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#5
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Re
All the hoses are ok and the radiator is new not insects or debris that can block it.
The presure cap on the coolant reservoir is also new. Coud be a small leak in the coolant reservoir that release the presure? It look old to me. I am trying to replace it . I am completly puzzled. Thank for your help, and maybe you guys have more Ideas. I was reading some postings that the termostat can be installed wrong or the fan wings are installed backwords. Do you belive in that ?
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New Addition to the family 2013 Passat TDI 5Miles 2004 E500 4MATIC Wagon 95k 1996 E300 Diesel 173k Sold 1993 300E 2.8 230k Sold 1994 E320 White Wagon 373K Sold Still dreaming about ....500E Radu Negru |
#6
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You could have a bad thermostat. These days, with parts made who knows where by anyone, quality is going to hell fast, so bad ones new in the box are not unheard of. I recommend you stick with Behr or Wahler only, get it at a good independent, the dealer, or here at FastLane. DO NOT buy one at AutoZone, etc, they usually are junk.
Yes, the coolant tank can leak, the plastic gets old. Check the hoses for pressure after it gets warm on the highway. Wrap a rag around your hand so you won't burn yourself, and squeeze the upper radiator hose. It should be quite firm. If it smashes down easily with sounds of moving coolant from the tank, you have a pressure leak. Usually have coolant loss on stopping with this problem, though. I would also check for a blown head gasket. Does the coolant tank hold pressure cold? If so, pretty good chance the head gasket is leaking, and this will cause overheating on the highway. So will dragging brakes, though. I suppose it's possible to put the fan on backwards, but this would cause overheating all the time. Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#7
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Check your af/h20 ratio.
No more than 50/50 mix If you have high af ratio, it will not transfer the heat back to radiator well. Other possible is air bound... |
#8
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re
head gasket is out of the picture because I have done it 10 months ago,and there are no simptoms related to this.
Also it seams that the system holds presure the radiator hose is firm(hard) and when is cold and open the cap it release presure(fsssssss). I am goin to change the termostat but I know is Behr.I will never put any think from aftermarket. Does anybody know wat it suppose to be the temperature at hwy speds with the ambiant temp 85 F? How can I check the accuracy of the gauge?
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New Addition to the family 2013 Passat TDI 5Miles 2004 E500 4MATIC Wagon 95k 1996 E300 Diesel 173k Sold 1993 300E 2.8 230k Sold 1994 E320 White Wagon 373K Sold Still dreaming about ....500E Radu Negru |
#9
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#10
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Quote:
1) The fact that your engine runs warmer on the highway implies that it is getting hotter while driving. 2) The fact that it is cooling down in traffic implies that it is capable of cooling itself sufficiently. I just went through this uncomfortable process with a friends car, the cylinder needed to be machined due to the imperfections and now the engine temp is rock steady at 85-C. Valve job performed within the last 2 years………….IMHO I would encourage switching to a wood scraper (finishing scraper) when cleaning the cylinder head surface, it is faster. |
#11
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I agree completely with the last post, my guess on reading your statement that there is cold pressure was a bad head gasket or a cracked head. Since cracked heads are rare on the M104, I'm betting the gasket has failed, either for the reasons listed above or by the use of a defective gasket (some aftermarket ones are problematic).
Overheating under load with cold pressure is a sure sign of exhaust in the coolant. Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
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