1989 525i question....head gasket?

hey guys, I know this is a little out of category but you all have always helped in the past........I am looking at buying a 1989 525 with the 6 cyl motor. It is rough and needs to be brought back to it's glory. I have always been an E46 guy, so I am little out of my comfort zone here. The issue it is having...well, one of them....it will start and run great, but after sitting at idle for about 20 minutes it will start to the hot side and with the reservoir cap off you can tell there is a problem. The coolant will bubble up and overflow out of the reservoir but not like a geyser......I tried to use a block tester but I cant get the gas up bcs the coolant is too high in the reservoir. The coolant looks like crap and needs to be flushed, it looks more like water....the lower radiator hose is not getting warm, so I am thinking maybe the tstat could be screwed...or maybe the water pump? Id love to get her and bring her back to life but it is not worth putting a head gasket on it. Is there any way to tell FOR SURE the head is ok? ok guys, I cant wait to hear the feedback!

that's the same engine as the e30 325 if I recall correctly
Two ways to test if head is cracked is to "Pressure Test" the cooling system or have a dye put in at a radiator shop.

Therm stuck closed most likely. Change it before you buy the car, it's easy on M20s.

Originally Posted by lcoleman

Therm stuck closed most likely. Change it before you buy the car, it's easy on M20s.

+1.
Sounds like closed thermostat.

yea...that would be cool, I dont want to fix it and then have the guy jack the price up on me!!!! if it sounds like tstat to you guys, which I do trust, everything you've told me on my 330 has been right, for $500 I think Ill pop on it and go from there....are those engine as much as a pain as newer ones?

well, made a deal for $550, so, we will see what happens!! What if I ran it with no tstat at all and see what happens....would that make it easier to bleed maybe?

If the Head gasket is blown, your coolant would get into your oil. Quick way to check is pull the dipstick. If it looks like a chocolate milkshake, you got coolant in your oil.

Well the gasket to keep the coolant and oil sperated is ok, the oil is fine and the coolant is not milky either, Im worried it is popped on the exhaust side.....

Doing the headgasket on an M20 is a very easy job, besides, you'll want to change the timing belt if you don't know when it was last done and that's half the work in doing the headgasket lol.

Originally Posted by geoffriehl

Im worried it is popped on the exhaust side.....

No therm is fine, won't make bleeding any different, +1,000 on doing the timing belt asap.

ok, my plan is to take out the tstat and put it in boiling water and see if it opens or not.....and go from there, who knows, he hg sounds easy enough.....i have done tougher jobs....may be worth it...

well, some dude offered the guy $1,000 for it and I said he can have it! So, I bought a 1976 Mercedes 300D that doesnt run....fun!