Okay -- query for the engine experts. I'm putting an '85 back to life with about 65000 orig miles.

Status: Compression 135 ft/lbs (about an 8% difference, to the lower, on the front 2 cylinders, ~126 or so), and the torque seems good on the head bolts.

I know that a headgasket is likely to need a replacement about 100k, and I'm seeing some white smoke out the back...and there's about only one place to look...

Is there any other vector leakage could occur in that might make more sense? Mileage wise it seems a bit young, but sitting unstarted for 6 years will do damage to about everything.

 

The another thread going about cracked blocks. You might wanna read up.

But.......

How much white smoke are you getting and how long does it last? If you take the car out for a good run....30 minutes or more, let's say....are you still getting smoke? If the car doesn't get used much quite a bit of water can accumulate in the mufflers.

Cheers
DD

 

Oof, yeah, there is that option. I'd figure on some mixing of oil in the coolant, but worth considering.

 

K&W Block Sealer is a great product for fixing head gaskets - just do exactly as the instructions tell you. I used it last week to fix a white smoke situation which avoided a costly teardown of a turbocharged engine. It has been known to last for a few years. It is sodium silicate or water glass based but contains additional fillers. Check out this video.

 

My nickel:

I'd work on the water condensation in the mufflers theory first. and/ it may perfectly normal. In cold weather my healthy cars do some white smoke. Kinda neat, twin plumes with a nice burble as it warms up! As the jaguar muffler's lie at an angle, the lower side is prime for water to gather. Some advocate small holes at the low points.
I've seen those "weeps' in other mufflers as well.

Sodium silicate is an old machinist friend to seal "weapers". I've a bottle of it in my shelve. thought I might use it on a past project. It worked and did not leak as I had a cure. Old adage, have it and you will not need it. of course, the converse is equally true.

Trouble is with these things, they seal everywhere good or bad!! As they go, KW is a reputable product. My son used it a time to prolong the life of a race engine with a crack in a bore!! Disposable type of racer, anyway!!

Carl

 

Of course you can get white smoke from oil burning too.

 

I've always seen the smoke from burning oil as a ilght blue! I've had my share of them!!

 

A main thing to look at is water in the fuel tanks. This can occur both from condensation over time and more commonly from rainfall where the water sips in around the fuel tank lids. There are evacuation hoses going from the recess around the tank lids that is supposed to drain water away but it can become blocked from varios sludge. And in U.S extreme weather rain can fall at a quicker rate than the drain holes can keep up with. This in combination with that the rubber gasket on the tank lid can have tiny cracks so that excess water will easily pour in (during a whole night of rain) will complete the water immersion. Since water is heavier than the petrol it collects at the bottom of the tank where the fuel outlets happen to be. So the water will be the first thing to exit into the fuel lines.
This can result in hard starting, misfiring and white exhaust.
There are drain bolts at the bottom of the tanks that can aid in evacuation of any water buildup.

 

Regarding head gasket sealer chemicals; could eventually work but do not leave this chemical in the radiator for long, it results in sediments that could totally block the radiator so the engine overheats and results in the opposite of what you hoped.

Back in the 80s I ran a XJ Series 1 on the famous Wondarweld chemical in an attempt to cure a water leak into #1 cylinder. I left the mix in the radiator for too long and it did no good to cooling efficiency. The real problem was an old clogged radiator that just needed replacing, and the infamous crack in the block between cyl #1 and 2. Replacing the radiator and hoses would have saved the engine early on. Somehow I falsely assumed in those days that a new rad would be prohibitively expensive. At one time an ageing lower radiator hose exploded just after parking and the hot engine lost all fluid rapidly. Just examples of how not dealing with the real problems caused series of incidents.

Good checklist for XK engine longevity is:
- Fresh radiator for good cooling efficiency.
- Radiator cap not leaking so that hot coolant pressure can hold (pressure raises the boiling point. Low pressure increases the risk for boiling).
- Fresh water hoses so that they withstand the 1 kg/sq cm pressure.
- Working thermostat.

 

White smoke can also becaused if the brake master cylinder is leaking back into the brake booster; which uses vacuum from the inlet manifold and brake fluid can be sucked in and burn as awhite smoke.this can happen if the car has sat for a long while and the seals in the master cylinder deteriate and brake fluid can leak back into the booster.


Ray