735I COOLING SYSTEM

1973 BMW 740

Tiny

maxmoves64

November, 21, 2007 AT 10:30 AM

Hi all and hope you can help. I bought a bmw 735i, England, last week. It has 86,000 miles with a V8 3.5ltr 5 speed steptronic gearbox. I bought the car and drove 50 miles home with no problem but the following day I had a 90 mile journey and 3 miles from my destination, m the temp gauge shot up and I pulled into a garage within 2 mins only to have the expansion tank lid blow off! Of course it was undriveable after that. It was taken back home and I drained the rest of the fluid and replaced the expansion tank. I turned on the heaters full and slowly topped up the tank to make sure that all the air was released and I could see the coolant dropping and bubbles coming up through. Once the engine had reached its normal running temperature and the coolant level was correct, I watched this and let the engine run for half an hour and replaced the cap. I then went out for a drive and after about 40 miles the heater stopped working and only cold air came through. I got back home and waited for the engine to cool and then topped it up again. Where is this coolant going and why? I can`t find any leaks but you can smell coolant in the car cabin after a while. The thermostat is operating and so is the waterpump but I can`t locate the problem. Any ideas? Thanks and look forward to your help.

FOUND 509 RELATED QUESTIONS

1 Answer

Tiny

Dr. Hagerty

November, 21, 2007 AT 1:57 PM

Has a cooling system pressure test been performed? Also what is the production date of the vehicle(open the drivers door and look for the sticker on the " B" pillar) The V-8 motors have a tendency to leak at the valley pan (under the intake manifold) at the mileage you quoted. There are quite a few age and mileage related issues that go along with ownership of the V-8 motored BMW automobiles. Cooling systems that utilize plastic require periodic replacement of components, as you have seen.

Please login or register to post a reply.

Cabin Air Filter Replacement Honda Civic
Window Switch Replacement and Test
Cabin Air Filter Replacement Chevrolet Tahoe
Cabin Air Filter Replacement Saturn Vue
Window Regulator and Motor Replacement Honda
Cabin Air Filter Replacement