weird smoke and overheating [Archive] - Bimmerfest - BMW Forums

: weird smoke and overheating

09-26-2008, 01:25 PM
so i have a 1990 525i with a larg amount of mods done too it
and i went out fo a nice sunday drive (i had noticed it getting a little hot the day befor but nothign major) and when i was pulling into my house the heat started to max out

i got home shut it off poped the hood and it had smoke coming out from the exhaust side of r the motor looked liek around the spark plugs and i waited for it to cool down

next morning check the oil no water in it changed the oil and flushed the motor checked for water in the oil

flushed the coolant no oil in the ater ot anyhting like that bleed it and jsut sittign at idle the thing started to heat up and max out with in 10 minutes

im not sure what to check since i dont see where the smoke is really coming from and i have no water in the oil or the other way around

plz god dont say i jsut blew a new head that i put on the week befor ???

help me otu guys

bimmer dot info
09-29-2008, 10:32 AM
How long did you drive it after the heat went up?

10-01-2008, 02:32 AM
if you run it with the header tank cap removed do you have air bubbles comeing up into it ?you say you replaced the head ,was this the gasket or both. was it a new head or second hand if it was second hand or your original head did you get it skimmed properly,ally heads should always be skimmed as after overheating they tend to go out of shape upon removal and trying to clean off old gasket residue can lead to an uneven surface.did you put the thermostat back in,is it working correctly? if you leave the thermstat out vehicles generally run cooler but once they start to heat up they usually carry on gettin hotter as the water isnt retained in the radiator long enough to cool down before being allowed into the engine. my 525tds heats up quickly but maintains running temperature,there you go didnt say it is your head!!!good luck

10-01-2008, 02:41 AM
forgot to mention how good is your radiator ?if your engine is heavily modded the thing will be producing more heat anyway and your rad may not have enough capacity to cope.i wouldnt worry too much about wierd smoke that will be smeech because the engine was that hot even oily fingerprints will burn off (no flames!)does it still run ok?

10-02-2008, 08:02 AM
i prolly ran it no more than 3 minutes just enough time to get into my drive way, and its a new fully built head thats ported and polished i still have the same thermostat in it that was in when i bought it which was prolly never replaced considering the fact the old head had the orginal spark plugs in it, the smoke thing freaked me out since befor the new head i would run it strong for a bit and hier would be a lil bit from aroun the exhaust side but not alot but it prolly just grease and oil on the block no smoke of any kind coming out of the exhaust.. im just worried about it being one hting and fixing another since thiers no oil in water or other way around.... it runs fine also but it will idle for about 10 minutes and hit normal running temp and then creep up from there if its just idleing i have a diffrent radiator in it than stock and a cooling fan im really worried about it though so its just siting on the stands till i can figure out what exactly it is cuz i guess with no other sign of a blown head gasket id have to take the head off to know for sure =///

bimmer dot info
10-02-2008, 11:38 AM
Bleed it more.

10-02-2008, 12:40 PM
jesus god how long does it take to belld this motor haah it took me like an hour and its seriously still got air in it ??

bimmer dot info
10-03-2008, 07:04 AM
Have you used both bleeders?

10-03-2008, 08:57 AM
the one on the t-stat housing and the one by the radiator overflow tank

bimmer dot info
10-03-2008, 09:44 AM
That would be them. Give it a few more tries. They can be a real PITA.

10-03-2008, 10:13 AM
ahahah most definatly