Blown head gasket scenarios/ diagnosis

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BL8R29
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Blown head gasket scenarios/ diagnosis

Post by BL8R29 »

I swear I smell water in my exhaust and I think I see it coming out of my oil cap when I open the oil cap with the motor running but I really do not have intrusion into my oil so it’s super trippy just trying to figure out the best way to diagnose..

I tested the coolant with the blue liquid stuff and no color change-o
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dlb
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Re: Blown head gasket scenarios/ diagnosis

Post by dlb »

When I'm trying to diagnose a bad head gasket, these are the key things I look for:

- running poorly, but in an odd or inconsistent way
- consuming coolant (I check the overflow reservoir each morning before I start the car)
- low compression test results on two adjacent cylinders

There are other things people look for, like chocolate milk-ish residue on the underside of the oil cap, and bubbles in the coolant if you take the rad cap off, but the three things I listed first have worked reliably for me. Plus I had an air-cooled VW Vanagon and it perpetually had chocolate milk on the underside of the oil cap so I've never felt that one was a very reliable method.
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NWMO
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Re: Blown head gasket scenarios/ diagnosis

Post by NWMO »

BL8,

How is the car running/driving? I tend to look for coolant in my oil. Small amounts show up as whitish and/or light brown specks on the dipstick. I have some blow-by (though the car is running well) and if I remove the oil filler cap with the engine running, it will spit some at me, but it’s just oil. If really concerned, the compression test is the way to go.

David - the underside if the cap isn’t a bad spot to check. I would suspect the air-cooled engine experienced “interior” condensation causing what you saw.

Chris
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dlb
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Re: Blown head gasket scenarios/ diagnosis

Post by dlb »

NWMO wrote: Wed May 17, 2023 8:59 am

David - the underside if the cap isn’t a bad spot to check. I would suspect the air-cooled engine experienced “interior” condensation causing what you saw.
I agree, there must have been some moisture in there somehow but it made me wonder, if there was moisture even in my air-cooled engine, couldn't the same happen to a regular engine? And I've seen similar on my cars which have definitely not had bad head gaskets, so it just hasn't seemed like a reliable diagnostic for me. Not saying it can't work, just not one of my go-to's.
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Re: Blown head gasket scenarios/ diagnosis

Post by NWMO »

I wondered if it may be more common with air cooled engines? I’ve not seen it on water cooled engines hardly ever, unless there was an issue.

Chris
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BL8R29
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Re: Blown head gasket scenarios/ diagnosis

Post by BL8R29 »

NWMO wrote: Wed May 17, 2023 8:59 am BL8,

How is the car running/driving? I tend to look for coolant in my oil. Small amounts show up as whitish and/or light brown specks on the dipstick. I have some blow-by (though the car is running well) and if I remove the oil filler cap with the engine running, it will spit some at me, but it’s just oil. If really concerned, the compression test is the way to go.

David - the underside if the cap isn’t a bad spot to check. I would suspect the air-cooled engine experienced “interior” condensation causing what you saw.

Chris


It runs great..

I cant for the life of me find water in my oil…

But I definitely have some white smoke and a strange stink to my exhaust..

I guess compression test is the call?

Recommended tester? To buy
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SirFoxx
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Re: Blown head gasket scenarios/ diagnosis

Post by SirFoxx »

BL8R29 wrote: Tue May 16, 2023 11:17 pm I swear I smell water in my exhaust and I think I see it coming out of my oil cap when I open the oil cap with the motor running but I really do not have intrusion into my oil so it’s super trippy just trying to figure out the best way to diagnose..

I tested the coolant with the blue liquid stuff and no color change-o
on these cars, coolant in oil failure mode is very rare in my experience.

dont be looking for a problem if there is not one. if you dont have exhaust gas leaking into the radiator, and your coolant level isnt going down consistently, then your head gasket is fine. its normal for a minor amount of steam to come out of the exhaust due to condensation. the engine would have to be drinking more coolant than gas for it to be noticeable in the exhaust.

also water doesnt have a smell, so im not sure what youre smelling coming out of the oil cap. probably aerated oil. and smelling it is not the right way to check. the thing to look for is an excessive amount of milky oil on the cap. However, even then, thats not a good indicator as its normal for condensation to form in the engine, and to get mixed around a bit before evaporating.

I personally like using the tester that you have to physically hold on the spark plug hole vs the screw in ones. the cheapo screw in ones have screw on adapters for the different thread pitches, and they always get stuck in the head when trying to unscrew them :(

make sure to unplug the dizzy and hold the throttle wide open when doing the compression check.
1988 DLX 4wd Tercel Wagon w/ weber (RIP)
1985 4wd Tercel SR5 (RIP)
1986 Base 2dr Hatch (RIP / PARTS)
1986 DLX 4wd Tercel Wagon with ???
1985 DLX 2dr Tercel Hatch w/manual swap
1981 2dr Toyota Tercel w/7age (RIP)
1981 3dr hatch Toyota Tercel w/Turbo 4AGE
1981 3dr hatch Toyota Tercel SR-5
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Re: Blown head gasket scenarios/ diagnosis

Post by Paul »

Here's a link to an affordable compression tester I purchased on ebay:
https://www.ebay.com/itm/281352084227
I bought it because my HF tester started giving misleading readings. There is a lightweight schrader valve on most testers that acts as a checkvalve... if it leaks you'll get false low readings.
If you still have the catalytic converter, strange stink and moisture are somewhat normal. This might be more likely if you have run the car for short trips, where the exhaust system hasn't heated enough to cook off all the accumulated moisture.
You can pull the plugs and look for signs. Shine a light into the spark plug hole and looks at the piston tops. An unusual clean looking cylinder might be an indicator.
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Re: Blown head gasket scenarios/ diagnosis

Post by dlb »

SirFoxx wrote: Thu May 18, 2023 6:33 am
dont be looking for a problem if there is not one. if you dont have exhaust gas leaking into the radiator, and your coolant level isnt going down consistently, then your head gasket is fine. its normal for a minor amount of steam to come out of the exhaust due to condensation. the engine would have to be drinking more coolant than gas for it to be noticeable in the exhaust.

also water doesnt have a smell, so im not sure what youre smelling coming out of the oil cap. probably aerated oil. and smelling it is not the right way to check. the thing to look for is an excessive amount of milky oil on the cap. However, even then, thats not a good indicator as its normal for condensation to form in the engine, and to get mixed around a bit before evaporating.

I personally like using the tester that you have to physically hold on the spark plug hole vs the screw in ones. the cheapo screw in ones have screw on adapters for the different thread pitches, and they always get stuck in the head when trying to unscrew them :(

make sure to unplug the dizzy and hold the throttle wide open when doing the compression check.
+1
BL8R29
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Re: Blown head gasket scenarios/ diagnosis

Post by BL8R29 »

SirFoxx wrote: Thu May 18, 2023 6:33 am
BL8R29 wrote: Tue May 16, 2023 11:17 pm I swear I smell water in my exhaust and I think I see it coming out of my oil cap when I open the oil cap with the motor running but I really do not have intrusion into my oil so it’s super trippy just trying to figure out the best way to diagnose..

I tested the coolant with the blue liquid stuff and no color change-o
on these cars, coolant in oil failure mode is very rare in my experience.

dont be looking for a problem if there is not one. if you dont have exhaust gas leaking into the radiator, and your coolant level isnt going down consistently, then your head gasket is fine. its normal for a minor amount of steam to come out of the exhaust due to condensation. the engine would have to be drinking more coolant than gas for it to be noticeable in the exhaust.

also water doesnt have a smell, so im not sure what youre smelling coming out of the oil cap. probably aerated oil. and smelling it is not the right way to check. the thing to look for is an excessive amount of milky oil on the cap. However, even then, thats not a good indicator as its normal for condensation to form in the engine, and to get mixed around a bit before evaporating.

I personally like using the tester that you have to physically hold on the spark plug hole vs the screw in ones. the cheapo screw in ones have screw on adapters for the different thread pitches, and they always get stuck in the head when trying to unscrew them :(

make sure to unplug the dizzy and hold the throttle wide open when doing the compression check.
Thanks! To clarify the strange smell and white smoke im smelling is from the exhaust..

Any idea the name of / brand of the nonthreaded compression test?
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Re: Blown head gasket scenarios/ diagnosis

Post by SirFoxx »

BL8R29 wrote: Thu May 18, 2023 7:50 am
Thanks! To clarify the strange smell and white smoke im smelling is from the exhaust..

Any idea the name of / brand of the nonthreaded compression test?
does it smoke cold, warm, all the time, first start up...?

are you running water or antifreeze?

ive got this one.

https://www.harborfreight.com/compressi ... byEALw_wcB
1988 DLX 4wd Tercel Wagon w/ weber (RIP)
1985 4wd Tercel SR5 (RIP)
1986 Base 2dr Hatch (RIP / PARTS)
1986 DLX 4wd Tercel Wagon with ???
1985 DLX 2dr Tercel Hatch w/manual swap
1981 2dr Toyota Tercel w/7age (RIP)
1981 3dr hatch Toyota Tercel w/Turbo 4AGE
1981 3dr hatch Toyota Tercel SR-5
BL8R29
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Re: Blown head gasket scenarios/ diagnosis

Post by BL8R29 »

SirFoxx wrote: Thu May 18, 2023 8:25 am
BL8R29 wrote: Thu May 18, 2023 7:50 am
Thanks! To clarify the strange smell and white smoke im smelling is from the exhaust..

Any idea the name of / brand of the nonthreaded compression test?
does it smoke cold, warm, all the time, first start up...?

are you running water or antifreeze?

ive got this one.

https://www.harborfreight.com/compressi ... byEALw_wcB

On startup definitely…

Sometimes randomly more than other times while driving

Green antifreeze
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SirFoxx
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Re: Blown head gasket scenarios/ diagnosis

Post by SirFoxx »

BL8R29 wrote: Thu May 18, 2023 8:50 am
On startup definitely…

Sometimes randomly more than other times while driving

Green antifreeze
are you losing coolant?
1988 DLX 4wd Tercel Wagon w/ weber (RIP)
1985 4wd Tercel SR5 (RIP)
1986 Base 2dr Hatch (RIP / PARTS)
1986 DLX 4wd Tercel Wagon with ???
1985 DLX 2dr Tercel Hatch w/manual swap
1981 2dr Toyota Tercel w/7age (RIP)
1981 3dr hatch Toyota Tercel w/Turbo 4AGE
1981 3dr hatch Toyota Tercel SR-5
BL8R29
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Re: Blown head gasket scenarios/ diagnosis

Post by BL8R29 »

SirFoxx wrote: Thu May 18, 2023 10:27 am
BL8R29 wrote: Thu May 18, 2023 8:50 am
On startup definitely…

Sometimes randomly more than other times while driving

Green antifreeze
are you losing coolant?
Not on the probably.. 35 minute drive i went on yesterday… driving it today too so we’ll see
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dlb
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Re: Blown head gasket scenarios/ diagnosis

Post by dlb »

Make sure to always check your coolant level at the overflow reservoir, when the engine is stone cold. I find this is the easiest way to track if there is any coolant loss.
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