Sputter and cloud on startup!

[Danno87]

I recently did a 4.0 swap in my 87 b2 got it all done and fired it up. Ran great. Took er for a drive all is great. After setting for about 30 minutes to tidy up tools I go to fire it back up and it starts missing for a few seconds and blows a heavy cloud out of the tailpipe. I don't see any oil in the coolant nor vise versa no sweet exhaust. I get a few bubbles in the coolant. How else can I sure fire test an intake leak? I didn'tgo as far as h gaskets. They were new on the engine. What do I do now? It's been a mnth of work on this truck. Please help me .

 

[Andy D]

Total guess, check the fuel injector wires. one may have broken right where they go into the plug.

 

[Danno87]

Haha. I thought of that. They look good. It only misses for a total of maybe 2-3 seconds. Then smooth

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[Danno87]

I'm wondering if the coolant system is under pressure and as I shit down it builds and sends coolant into the cylinders. I just wanted a second opinion on it and maybe another way to test it before I tear back into the top end.

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[Danno87]

I'm literally afraid to drive it. Haha.

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[Danno87]

Ok on further testing on a cold engine, I took the radiator cap off and started the truck. Coolant immediately started flowing out! Is this a sign of H gasket problems? This is my only vehicle and have been pedaling the streets to work and back for weeks now would love to have a car to drive. Any help or advice would be greatly appreciated.

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[RonD]

Do the Glove Test.

Remove rad cap
Remove overflow hose, plug this outlet
Drain a little coolant out, so it is about an inch down
Disable Coil, pull it's connector off, you want a no start
Put a latex glove over rad cap opening and seal it with rubber band, or use a balloon or even a condom will work

Cooling system is now sealed

Crank engine and watch glove
If it starts to bounce you have a cylinder leaking pressure into cooling system, blown head gasket

If it just lays there then you don't

If it does bounce, remove 1 spark plug at a time and crank engine again
When it stops bouncing last spark plug removed was from the leaking cylinder.
Re-install it to confirm.

 

[Danno87]

That's a great idea but I ended up doing a block test with the bulb ,fluid and tube tester. Fluid stayed blue throughout the test. As far as the head gaskets are concerned I think they are ok. How do I tell if the bubbling is an intake coolant leak?

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[kimcrwbr1]

The smoke on startup could be valve guide seals? You can change the seals without pulling the heads. I would do a leakdown test and if the head gasket is leaking put in new valve guide seals while you have the heads off! If it passes the leakdown go ahead and change the valve guide seals. Oil in the exhaust will cook the cat/s in no time.

 

[Big Jim M]

Danno do the glove test! All indications are you have a compression leak.

If on a cold engine the coolant boils out on start up then you DO HAVE a compression leak.
Don't try to overlook this fact! Do the glove test.
Intake leaks will not boil out the coolant.
Big Jim

 

[enjr44]

I think, for what that is worth, that an intake leak would either run down the outside of the engine or be sucked into it. I don't think it would push air into the rad.

Is the temp gauge going up and down? Sort of wandering around? They do that if the cooling system is not full. It will also push coolant out of the rad (with the cap off) if it is pushing a large bubble out of the engine. What color was the smoke and how long was the test drive.

Once while working on a poorly running engine I would start it, let it idle for say ten minutes, shut down and let it sit, and repeat for a bunch of times. I got white smoke out of it for at least 5 miles (on a warm day) when I got it back on the road. The exhaust system was full of water from all the short run times.

Bubbles are from a system that still has air in it from refilling (after it was empty) or compression gasses. You did a block test and got nothing, so just for grins, do the glove test. Drive is some and watch the coolant level. A bad head gasket should fill up the coolant recovery tank as it pushes coolant out of the system.

 

[Danno87]

Ok. So with all the great advice you guys had. I did a whole series of tests that confuse me but one. I did a block test 3 times with the fluid staying blue. I did a compression test with all cylinders running g between 185-190 (dry) I did a coolant test with no visible drop for close to 45 minutes at 30 psi. The funny thing is. As I did the compression test all of the left bank. 123 had cavitation in the radiator. So that was basically my glove test. It was a tuff one to find. I think it is a bad hg. Thanks for all of you help!

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[Danno87]

Unless there is something I'm missing.

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[Danno87]

It doesn't seem to ever overheat when I do drive it. No white smoke except rare startups after warm and sitting. Guage is steady. E fan seems to be consistent with the guage. I did notice a slight tinning color on the 12&3 spark plugs that 45&6 didn't have. I got a few 9 inch cotton swabs and tried to see if I could get coolant out of a cylinder but none. It is bugging me. I really want to drive this thing. So In Your best judgment would u drive it untill you can afford a good gasket set or let er sit?

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[enjr44]

Coolant on the plugs would make them look steam cleaned. No color at all. coolant is a really good at removing carbon. One thing you can't do is let it over heat. One time and it will cause damage. So driving it may not hurt anything that is already broke; but, over heating these engine sure as hell will......