blown head gasket?

[synamin]

i’ve been having overheating issues and i’ve even seem white smoke and bubbling in my coolant tank. i know these are signs of a blown head gasket but i also just found my coolant bleeder screw is stuck in the up position. it’s not screwed in all the way and it’s rounded off so i got to remove it somehow. my question is could that be the reason for bubbling and overheating or is my head gasket blown?

[95BMWIC]

You would be leaking coolant if the bleeder screw wasn't screwed in properly.. not sure what you mean "up position" - I believe the e model is the same as the i model and it should be sitting on the top of the thermostat..?

Probably the quickest and easiest way to check for a head gasket leak is to run a quick compression test on the cylinders. If you have unequal compression (and with your other symptom) it would "confirm" a head gasket leak.

If you haven't done this before - its easy and I could list out the instructions if needed- you just need a compression gauge..

[msservices]

Funny story...I once thought I had a blown head gasket because of the bubbling in the coolant tank...so sure that I rebuilt the whole top end of the motor, only to have it bubble through the tank again. Turns out radiator/overflow caps have inner and outer seals on them. Mine had a bad inner seal, so even though coolant wasn’t coming out it wasn’t holding pressure in the system. So A five dollar radiator cap solved the problem. Different car, with a Chevy v8, but same principle

[synamin]

thanks for your input and i mean like it’s screwed in half way but it looks like it was being bleed and somebody forgot to screw it all the way down. i’ll give the compression test a shot. if your willing to give me the instructions that would be appreciated

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i actually saw somewhere while i was looking at symptoms. i’ll give it a shot. i haven’t really seen any other symptoms besides bubbling so i pray that’s my issue lol man i’ve spent so much money on my e30 and haven’t even done any body work yet

[superj]

did you tighten that bleeder down?

[synamin]

tried too but it’s stuck. i ordered a new one but i have to figure out how to remove the old bleeder and i fucked up and rounded it off

[superj]

vise grips or anything that grabs it. what caused it to be so tight that it rounded off though, is my question. once I break the initial torque free, mine turns by finger tip

[msservices]

Somebody here may be able to sell you a new housing if you want to spare yourself the agony. Aluminum can corrode with itself and other metals with a vengeance

[superj]

yup, that's true. dissimilar metal corrosion is terrible and will exfoliate both metals and lock them together

[95BMWIC]

thanks for your input and i mean like it’s screwed in half way but it looks like it was being bleed and somebody forgot to screw it all the way down. i’ll give the compression test a shot. if your willing to give me the instructions that would be appreciated

i actually saw somewhere while i was looking at symptoms. i’ll give it a shot. i haven’t really seen any other symptoms besides bubbling so i pray that’s my issue lol man i’ve spent so much money on my e30 and haven’t even done any body work yet

You mentioned "overheating" in your first post - this is also a symptom.

You can "borrow" a compression tester from almost any national parts store - so no need to purchase one.. If you have a harbor freight - they are around $30..

The process is simple -

Pull Main relay
Remove spark plugs
start from cylinder #1 and screw in tester - make sure it is sealed in (tight)
Put tranny in neutral
Push throttle to the floor
Crank the engine a good 5 - 6 revolutions
Record the value on the gauge
Move to the next cylinder

Compression should be somewhere between 140-160psi (for all models) and it should be fairly even across the 6 cylinders.

If you have any dramatic differences in pressure - it most likely is a head gasket failure.

Other things to look for (besides overheating issues) - does your heat suddenly go away (heater on in the cab) - is there wetness under the head (on either side), is there white frothy oil inside the oil cap..

If the bleeder screw is seized - you could try heat from a torch or a few days of penetrating oil - but I would first figure out the head gasket issue.. as long as it is not leaking..

[msservices]

Sounds like he is just speculating the head gasket because of the bubbling in the tank. The white smoke could indicate that or it could be running rich, burning oil through valve guide seals, etc. Usually a blown head gasket would billow white smoke if it breached a coolant passage, Because the coolant is under pressure as it’s heating up and the cylinder is under vacuum %25 of the time, and yes it would be forcing combustion air into the cooling system another %25 of the time. Also the weak point im the m20 seems to be the Siamesed cylinder walls where there are no coolant passages, and that seems to be where they typically fail, but anything is possibly on a 30 year old car. When my m20 was overheating because of the blockages in the radiator, it would bubble also, I’m not sure if that’s because of the coolant boiling, or if the blockages in the radiator caused air pockets to stay trapped in there as well, thus eventually rising back to the top of the radiator and out the easiest/highest path which happens to be the coolant tank (once the car is shut off and the water pump is no longer trying to push/pull the coolant through the radiator core)

[synamin]

okay thank you! i’m going to try a compression test this week. i managed to get the bleeder screw out and i put the new one in but it wouldn’t screw in all the way. starting to think that’s just as deep as the screw will go

[synamin]

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IMG_1235.jpgIMG_1233.jpg

okay I tried uploading pictures again. that's how far in the bleeder screw goes, thats the old screw that I got out now the new ones in that exact same position, doesn't reach the bottom. and that's how my coolant cap looks like. it definitely looks different that the oem one I see when I search it up

[aaverhulst]

You might try this from Oreillys, free tool rental. I have never used one but might be a good test for you.
https://www.oreillyauto.com/detail/b...q=block+tester

[95BMWIC]

Bleeder screw position is fine - it doesn't screw in to the point it bottoms on the housing. But you should replace it since it was stripped - easier when you go to bleed the system of air.

Most likely your cap is fine as long as it seals and threads down. - To be sure does it have a BMW logo on it? If it doesn't, it may be an aftermarket cap and could be bad - but hard to tell for sure. You could do a pressure test on the system (almost any garage can do this).

Before getting the cart ahead of the horse - just run a compression check - its simple and free (if you can be lent a tool) and can eliminate or confirm a diagnosis. Again time (effort) and money (free) are low and you get a good picture of your engines health. Then you can move forward on spending more money and more time (like a system pressure check).

[synamin]

alright thank you. i’ll do the compression test as soon as i get a chance

[H.J. 1981]

Vice grips indeed, mine was rounded and over tightened, like every single bolt and nut the PO shop did on the car, except that the head bolts were surprisingly loose, i could remove each cylinder head bolts without any force or pressure, as if they were tightened to 20nm and done.

[synamin]

Okay guys did a compression test! my results all my cylinders were 190-200 except #5 which was between 160-170. my car is stroked so maybe that's why it's higher? not sure. tell me what you guys think. also bad news is there's definitely an oil leak. there was oil found on my spark plugs and on the compression tester thing. here's pictures. how bad is it?
IMG_1244.jpgIMG_1247.jpg

[superj]

the oil is just on the threads? if so, that could just be oil running down from the valve cover gasket and into the plug ports. oil where the plug actually sparks will cause blue/grey smoke from your exhaust and would be valve seals or rings, which are found by particular compression testing. wet and dry testing tells you if its the rings and also, if it smokes primarily on start up and deceleration, that's usually valve seals

[msservices]

So now back to why the coolant is bubbling...
https://www.bimmerforums.com/forum/showthread.php?2403238-E30-M20-Overheating&p=30252873#post30252873

[synamin]

the oil is just on the threads? if so, that could just be oil running down from the valve cover gasket and into the plug ports. oil where the plug actually sparks will cause blue/grey smoke from your exhaust and would be valve seals or rings, which are found by particular compression testing. wet and dry testing tells you if its the rings and also, if it smokes primarily on start up and deceleration, that's usually valve seals

oil on thread and is there suppose to be a build up of oil under my valve cover? I'm not sure if thats normal or not. its in the picture on the bottom there's lots of oil

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I've replaced my radiator and thermostat. you think I should also replace all the hoses?

[msservices]

Okay, so having a new radiator and thermostat is throwing me a curve ball. When you say overheating issues, how hot is it reading on the gauge and does it change when you are stopped versus cruising speed?
Sounds to me like either you have air trapped in the system or the water pump is not circulating

[synamin]

haven’t driven the car in a couple months. if i start the car and turn the heater on and wait like 10 mins it’s automatically goes hot and coolant starts boiling/overflowing.

[msservices]

Did it operate at normal temps before you parked it, or did you replace the radiator and thermostat and then park it?

[synamin]

before parking, serious overheating issues. couldn’t drive more than 10 mins without coolant leaking and when it wasn’t over heating the gauge would still read slightly above the middle and below the third quarter