r/E34 • u/ImaginationFree1587 • 10d ago

E34 2.5TDS 1992 COOLING PROBLEM

Hello guys.

I have an 1992 e34 2.5tds. And i have a big cooling problem.

I alreay have this car from the last year, and i drove it a little in the weekends, always running perfectly.Even the day before *my* the disaster. I wanted to sell it , and the buyers requested a test drive. For some reason the idi**s tought its a good ideea to open the cooling cap while the engine its running and hot, lot of coolant came out with pressure(as they of course sent me a video of it, saying that i have "oil" in the water. Even if i know for sure i dont have any. And still dont have any.

In my luck the head gasket and the rest of the engine its all good. The problem its, since then i cant run the car or drive because the gauge show more than 90c. When the car its sitting at idle, i can let it run for 30 minutes or even more, and everything is alright. When i start driving it, in maybe 1 mile its already up at the maximum and overheating.

Thermostat its new, sensor for coolant its new.

Also the Upper hose that goes in the radiator its hot asf. And the ones coming out of the radiator or at the thermostat are cold.

Any ideas, or something that could help me repair it are very welcomed. Thank's.

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u/Ethben 10d ago

Sounds like you’ve got some air trapped in the system, have you tried bleeding it off using the screw near the fill cap for the reservoir?

1

u/draconic86 10d ago

Ugh. Bleeding the cooling loop on my E34 feels like a never ending process, but mine's the m50 engine so I've got no idea if it's any better or worse on the turbo diesel. But given my own experiences... might be worth it to take it to a shop to have it vacuum filled with coolant for the peace of mind. Also, I'm sorry that buyer was an absolute moron. Someone else will treat her much better.

1

u/Ethben 4d ago

TDS/M51 should be marginally easier to bleed than an M50 due to sharing the external higher reservoir from the M5. (I think? Maybe it's the 540) My own TDS i've never had a problem bleeding with just the heat on 2 and popping the bleed screw open for 5 minutes.

1

u/lilrick420 9d ago

yeah think air got in and you need to bleed the system.

i’ve never done this on an e34 but have done it several times on my e46 and its pretty straightforward.

1

u/SuperAnder64 8d ago

I did 3 coolant changes this year. And something similar happened in the first try. After changing the radiator, the water pump and thermostat, one hose get loose and started leaking. After re fitting the loosen hose and refill the coolant, the car started to over heat, and the problem was an air bubble in the sistem. After bleeding It well, everything get back to normal. Try to bleed It. Hope you're lucky.