Ugh.. pretty sure I have a blown HG or cracked or warped head

[rikyric]

FML...



Just bought the car for my son two weeks ago.

I've burped the cooling system numerous times, and every couple of days it is full of air again and starts to overheat at idle...

[dude8383]

Grab yourself one of these or something similar to be sure:

https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI

Perform a compression test as well.

[rikyric]

Ah cool! Thanks for the advise! Heading to the auto parts store now to pick one up.

[rikyric]

I picked up a combustion leak tester, but the problem is the coolant in the RT keeps overflowing wich prevents me from getting a reading. Coolant gets sucked into the tube with the blue chemical. So I can't see it turn green to yellow..

Any ideas?

[dude8383]

I'd drain some of the coolant out of the radiator then so you have enough time to get a reading.

[rikyric]

I'll give that a try

[rikyric]

Oh, on another note. I just picked up a complete m20b25 and getrag tranny out of a 91 e30 for $400!

[ak-]

Oh, on another note. I just picked up a complete m20b25 and getrag tranny out of a 91 e30 for $400!

Nice. Let it be your piece-of-mind build.

[e30davie]

If you are still concerned with the old engine, my suggestion is compression test and a coolant pressure test, that should tell you if the gasket is stuffed.

If you are going to just swap to the next engine, i suggest you do the same. Murpheys law states that your new "good" engine will have a blown headgasket too ;)

And its much easier to change a head gasket before you put that new engine into the car.

[rikyric]

If you are still concerned with the old engine, my suggestion is compression test and a coolant pressure test, that should tell you if the gasket is stuffed.

If you are going to just swap to the next engine, i suggest you do the same. Murpheys law states that your new "good" engine will have a blown headgasket too ;)

And its much easier to change a head gasket before you put that new engine into the car.

This is what I was thinking myself☝🏻

I actually bought it for the tranny, my second gear grinds. But could not pass on the $400 price for both motor and tranny. I will try to completely eliminate the current motors overheating issue. Before I make that decision.

[rikyric]

I've been reading that these engines are pesky when it comes to getting the air out of the cooling system. I think that I get all the air out, but then a couple of days later the overheating comes back and crack the bleeder on the thermostat housing and steam comes out, and frothy coolant.

[ak-]

Yeah, kind of sort of. Had to crack the bleeder of my brother's car maybe 3 days in a row of driving after bleeding when we changed his failed water pump till all the air was out.
Clutch fan in good shape?

[e30davie]

I've never had a trouble bleeding air out, just crack that screw when its running, and once again once its up to operating temp (so the thermostat is open) and i've always had a happy cooling system using that method.

By the sounds of your description you have a slow combustion leak into the coolant, which hopefully is just the headgasket but it can also be a cracked head, or worse a cracked block. The second two are unlikely but i've had them happen on other engines. but yer cooling system pressure test will tell all.

[rikyric]

Yeah I'm hoping it's just a blown head gasket. Ran out of daylight so I couldn't try the combustion leak test. But I did spot a leak coming from the expansion tank where the coolant level sensor is. I hadn't noticed the leak before because it had been raining all week. I thought it was weeping out the weep hole in the water pump. That's what it reminded me of when I saw it on the ground.

Hoping this is the cause. Fingers crossed

[rikyric]

Update:
I replaced the leaking coolant level sensor, got the temp up to the middle line and it held! I did do the newspaper test on the fan and it failed. So I'm going to get a new fan clutch and see what happens. I did notice after about 10 mins at idle the temp was slightly over the middle line.

Checked under the car and it wasn't weeping like it was yesterday. But had two small puddles, so I'll have to track those down.