Head gasket or inlet manifold

[white dolly sprint]

Hi
I am having trouble with the coolant level in my sprint.
The level keeps going down in the thermostat filler.
Bubbles coming up in the expansion tank when I switch off or when it has been run at high revs.
black like waiter coming from exhaust.
compression test is
Cold Hot
1 = 162 1 = 175
2 =170 2 = 185
3 = 163 3 =188
4 =161 4 = 190
Any advise on this before I commit to removing the head.
Thanks in advance
Mike.

[yorkshire_spam]

Depends on how you feel about head removal... if like me it fills you with a deep sense of dread then it might be worth buying a DIY test kit that does a chemical test for combustion gases in the coolant. I got one for about 30 quid when I suspected the head on the 1850 engine.
If you feel more casual about it, just crack on and pull the head off!

[xvivalve]

Those compression readings don't really suggest you have an obvious problem, though maybe one starting though with the low warm reading on 1. I'd follow Sam's advice first and test the coolant properly.

Black water from the exhaust is normal; petrol produces 10 x its own weight in water when it burns, some of which condenses in the exhaust and washes the soots out with it.

[Magenta Auto Sprint]

On a recent trip back from the Isle of wight last year, I was stopping every seven miles to top up the coolant in my 1850 Auto, I called the AA who couldn't find any leaks and suggsted a head gasket failure in the early stages of gestation . it now turns out that it was the pressure cap that was leaking as I found orange water stains in the nearside front wheel arch.

I too was dreading a head gasket change but it looks as if in my case it is not required.

Malcolm

[white dolly sprint]

Hi
Thanks for the replys
I also had bubbles coming up in the expansion tank.
There was a good stream at one point when the revs were up and another time a lot when the engine was switched off.
I have also filled the coolant up with a ltr of water several times when testing for this problem and not driving the car. The car was only running for about 10 minutes each time as I didn't want it to over heat with it loosing so much water but didn't see where the water was going.
Mike

[Carledo]

How does the engine oil look? And what (if any) colour is the exhaust smoke when you rev it? Finally, how hard do the water hoses get when the engine is running (and how quickly do they become hard) Overpressure in the cooling system is another good indicator of HGF, but don't be fooled by the blockage of the stat housing overflow pipe, which can give the same symptoms, but is far easier (and cheaper) to fix! Check this FIRST!

TBH I was more concerned about the air bubbling than any of the other symptoms, which, together, indicate head gasket failure.

Water loss with no visible leak and bubbling in the header are a good clue! But symptoms like this WITHOUT significant compression loss, MAY indicate a cracked head or a porous block, though if the latter is the case, you WILL find the missing coolant in the sump! The same goes for a failed water pump seal, a nearly "unique to Sprint" alternative cause of invisible water loss.

Steve

[white dolly sprint]

Hi Steve
Thanks for the reply
I have just run the engine on a high tick over and revved it a bit to warm it up for about 5 minutes as its not drivable and found.
There is no sign of any water in the oil or vise versa at the moment.
The top hose didn't get hard at all. I could squeeze it quite easily.
There was a small amount of steam looking smoke (if that makes sense) when I revved it but that could be that's its not properly warmed up.
I was wondering if a stuck thermastat could be the problem as the engine has been out of the car for the past 13 years. Also it didn't use much water this time so could of been an air lock as well.
I have ordered a head gasket test kit so will wait to try it before I pull it apart but I might test the therastat while I'm waiting.
I will let you all know how I get on but please keep coming up with suggestions.
Mike.

[cleverusername]

I have a slow leak on the inlet manifold, which I have been trying to cure for an age.

Look for staining starting at the junction between the inlet manifold and the head, running down the block. If that is the issue.

[white dolly sprint]

Hi
Removed the therastat and tested it, it was OK.
Found the very small 3mm hole in the thermast cover was blocked so was hoping it was that.
Put 2 tests on today first one is in jar and went this colour straight away. Second one took a few minutes longer. Its not loosing any water but turned green. See pic.
Mike.