Blown head gasket or stuck open fuel injector on 944?

[gawsies]

I'm having symptoms of a possible head gasket.. I've read other posts about it and seen it can possible maybe be a stuck open fuel injector?

Rough idle sometimes at startup for a min or 2.

I got a lot of white smoke come out from the exhaust maybe 3 times at start up in the past 3 months (I drive car 4 times a week)

Car does not over heat, I do get coolant loss and only 2 times the coolant leaked from the bottom (hoses?)

What symptoms do I look out for? What test can I do before I break the bank to get a head gasket job done lol.

Any help or advice is appreciated.

[Jfrahm]

Shut it off during the rough idle and look at the spark plugs.

White sweet-smelling smoke is coolant steam. But the plugs will tell us a lot.

[wwdwgs]

I second Jfrahm.

[walfreyydo]

Run a compression test.

[gawsies]

Originally Posted by walfreyydo

Run a compression test.

Spark plug are fine, look normal. Not wet or clean.

Compression test is interesting.

1-165psi
2-162psi
3-168psi
4-152psi

What does this

[gawsies]

Originally Posted by Jfrahm

Shut it off during the rough idle and look at the spark plugs.

White sweet-smelling smoke is coolant steam. But the plugs will tell us a lot.

Spark plug are fine, look normal. Not wet or clean.

Compression test is interesting.

1-165psi
2-162psi
3-168psi
4-152psi

What does this mean

[djnolan]

Did you run a coolant pressure test? You could drain the oil and look for coolant in the oil. is there coolant (milkshake) in the oil filler cap or the radiator cap? regarding the low compression on #4 it is not too troubling since it is within 10% but you could run a leak down test. Was the throttle open all of the way when you ran the comp test? Did you have equal number of cranks on each cylinder when you did the comp test? usually 5 or 6...

White smoke doesn't sound like fuel.

[walfreyydo]

Compression numbers at a minimum should be within 10% of each other. Yours are about 10% difference from 168 to 152.

Agree with djnolan, coolant pressure test is the next thing. Compression test doesnt always show a bad headgasket, especially with a small leak, but is always a good place to start.

If coolant system doesnt hold pressure, and there are no visible leaks, likely that pressure (and coolant) is going into the combustion chamber. Make sure your coolant tank cap is secure and holds pressure before doing so.

[gawsies]

Originally Posted by walfreyydo

Compression numbers at a minimum should be within 10% of each other. Yours are about 10% difference from 168 to 152.

Agree with djnolan, coolant pressure test is the next thing. Compression test doesnt always show a bad headgasket, especially with a small leak, but is always a good place to start.

If coolant system doesnt hold pressure, and there are no visible leaks, likely that pressure (and coolant) is going into the combustion chamber. Make sure your coolant tank cap is secure and holds pressure before doing so.

If it were to be that the pressure (coolant) is going into the combustion chamber, what will be the fix for this problem? And how bad is it?

Thanks for your help

[gawsies]

Originally Posted by djnolan

Did you run a coolant pressure test? You could drain the oil and look for coolant in the oil. is there coolant (milkshake) in the oil filler cap or the radiator cap? regarding the low compression on #4 it is not too troubling since it is within 10% but you could run a leak down test. Was the throttle open all of the way when you ran the comp test? Did you have equal number of cranks on each cylinder when you did the comp test? usually 5 or 6...

White smoke doesn't sound like fuel.

I haven’t ran a coolant test I would do that next. No there is no coolant in the oil filler cap.

I’m sure I cranked it around the same but I would do it again just to keep sure again.

[djnolan]

hello, the first step would be to rent a coolant pressure tester from autozone or other auto part store and to test the cooling system. The pressure tester connects where the radiator cap is, and has a pump to pressurize the system and a gauge to read the pressure. pump it up to 12 psi and watch the gauge to see if it holds at that pressure. it should hold for 30 minutes or more. if it is loosing pressure look for leaks such as loose hose clamps, fix and repeat the test. if it still doesn't hold pressure then it could be the head gasket.

here is an article https://haynes.com/en-gb/tips-tutorials/how-use-pressure-tester-find-coolant-leak

if you don't feel comfortable doing this test yourself take it to a shop.

[wwdwgs]

could it be an oil-coolant radiator?

[walfreyydo]

Originally Posted by wwdwgs

could it be an oil-coolant radiator?

This would not cause white smoke to come out exhaust, but would cause oil/coolant intermix

Originally Posted by gawsies

If it were to be that the pressure (coolant) is going into the combustion chamber, what will be the fix for this problem? And how bad is it?

Would require head gasket replacement and a bunch of "while you are in there" type work. Head refresh (resurface, valve seals, guides, valve job), timing/balance shaft belt + rollers, front engine reseal (if you have oil leaks), water pump, etc.

[djnolan]

Hi, also consider that if there is a coolant leak, coolant getting in the oil will rapidly damage the bearings if the engine is run. replacing bearings is considerably more difficult (or expensive) than a head gasket. so you should get to the bottom of this before driving the car anymore.

If you had a milkshake condition on the oil filler cap (or a lot of condensation) this would be a sure sign of oil in the coolant. for peace of mind you could drain the oil and see if there is coolant that will sink to the bottom.

[gawsies]

Originally Posted by djnolan

Hi, also consider that if there is a coolant leak, coolant getting in the oil will rapidly damage the bearings if the engine is run. replacing bearings is considerably more difficult (or expensive) than a head gasket. so you should get to the bottom of this before driving the car anymore.

If you had a milkshake condition on the oil filler cap (or a lot of condensation) this would be a sure sign of oil in the coolant. for peace of mind you could drain the oil and see if there is coolant that will sink to the bottom.

I don’t believe there is coolant in the oil, shows no signs in the oil cap and I’ve changed the oil twice this year and had no signs of coolant in there. I would be doing the coolant pressure test on Monday and see what happens with that . Any other thing I can possibly check?

[gawsies]

Originally Posted by djnolan

hello, the first step would be to rent a coolant pressure tester from autozone or other auto part store and to test the cooling system. The pressure tester connects where the radiator cap is, and has a pump to pressurize the system and a gauge to read the pressure. pump it up to 12 psi and watch the gauge to see if it holds at that pressure. it should hold for 30 minutes or more. if it is loosing pressure look for leaks such as loose hose clamps, fix and repeat the test. if it still doesn't hold pressure then it could be the head gasket.

here is an article https://haynes.com/en-gb/tips-tutorials/how-use-pressure-tester-find-coolant-leak

if you don't feel comfortable doing this test yourself take it to a shop.

Just did the coolant pressure test. I did have a small coolant leak because one of the hoses was loose and did another coolant test, started with 12psi and after 30min with no more leaks it was 11.5psi. -0.5 psi after 30min. Welp , head gasket?

[djnolan]

are you saying 12.0 dropped to 11.5 psi after 30 minutes? if so you don't have a coolant leak in the head gasket or elsewhere. 0.5 psi is within the margin of error or what would normally be lost.

[gawsies]

Originally Posted by djnolan

are you saying 12.0 dropped to 11.5 psi after 30 minutes? if so you don't have a coolant leak in the head gasket or elsewhere. 0.5 psi is within the margin of error or what would normally be lost.

Music to my ears lol. But why would I get white smoke occasionally? It has only happended 4 times in the last 4-5 months roughly. Maybe cause I didn’t use it for a week?

[Jfrahm]

Condensation. Does the smoke appear right away or after some time?

[gawsies]

Originally Posted by Jfrahm

Condensation. Does the smoke appear right away or after some time?

When it happened , it would be right away .