Blown headgasket ? Mixed symptoms

[Ex-User (107751)]

Just bought a ph2 172,
When starting up, even 1 hour after a long drive (engine still warm), I get white smoke out of the exhaust after 1 minute for about 2-3 minutes.
Never seen blue smoke before, but I think it's engine coolant - It smells sweet , and I lost about 0.5cm in the reservoir after 500km.
I get 145-150 psi compression at all 4 cylinders, and very strong gas smell every time I stop with an open windows - probably the decat.
Other than that , engine runs and idles smoothly, except "diselish" noise on cold startup .

There really is no professional to trust in this where I live, and I can't afford paying for the wrong job. How can I be certain what it is ?
Also should I drive it now ? I don't see anything special on the dipstick but don't know what to look for.

 

[Mr Plums]

definitely not condensation?

 

[Ex-User (107751)]

Not sure, how do I tell ? I believe this isn't normal, the smoke is thick and it lost some coolant.

 

[warwickstingray]

I had a fiesta that started doing this after a few motorsport events. Eventually the head gasket went spectacularly at an event and when we took the engine apart the clown that built engine had left lumps of old gasket on the block. Wasn't until it was used regularly in anger that it became an issue.

Can you still buy testing kits to tell you if there are gases present in the coolant. Or maybe a leakdown test at a local garage?

 

[Mr Plums]

Check for milky oil under oil cap, I havnt really heard of a head gasket go on these tbh.

 

[Ex-User (107751)]

Tried to shoot a video of this now, but it didn't smoke.
Not sure if it could be related , it had a big free-flow exhaust when I saw the smoke, now it has the original.

 

[Ex-User (107751)]

Not sure what to look for under oil cap, the oil was replaced a few days ago so it still doesn't have much color.
What could cause 150psi compression all around except a bad compression gauge?

 

[Dan@SJM]

150psi is very poor. Needs to be ~190.

 

[Ex-User (107751)]

What could it be ?

 

[Gaverick]

If the valve timing is off this could cause low compression on all cylinders. Not sure if it would cause the smoke you mentioned though.

Wrong timing is also quite common on these engines due to the fully floating cam pulleys.

 

[Addicted]

As above, it's very uncommon for a HG to go, though not to say impossible. I'd look into timing with compression that low imo!

 

[Ex-User (107751)]

I ran a leak-down test, got 3-6% on all cylinders. Is this even possible after 125K miles ?
If it is, does it mean the 150psi compression was false ?
Also does it rule out any internal engine problem and timing problem ?

btw we ran the test with the oil cap closed , is it ok ?