Quick sanity check... Coolant Loss/Head Gasket

[Conker]

Hi,

Just a quick sanity check...  I've searched the forum thoroughly and have diagnosed my current issue to be a head gasket fault. Here are the symptoms (1991 16v K-Jet):

1. In town driving, the coolant dissapears very quickly. In thirty minutes the coolant light starts flashing.
2. On a long motorway drive the coolant lasts a lot longer, at least 150 miles.
3. White smoke is coming from the exhaust at idle.
4. No mayo anywhere.
5. Car is running "okay-ish", sometimes a bit lawnmowery at low revs. It seems to want to run at very advanced ignition timings.
6. The car runs better when cold.
7. No coolant leaks are apparent. I've replaced expansion tank and cap and flushed the coolant. Fan cuts in as expected.
8. Car only overheats when coolant runs out.
9. Oil temp is fine.
10. Oil is being used but nothing too bad, approx a litre every 500 miles.
11. I haven't done a compression test as I would have to buy the kit and have no idea what to get. Plus the diagnosis seems fairly certain.


So, previous posts say a head gasket leak is most likely, and I can't think of anything else it could be?? I've read elsewhere that ignition timing issues (mine has an issue - its possibly a tooth out) can cause coolant loss and smoke out the back, but this sounds unlikely??


So the question is... Before I pull the head off, can you guys think of something I might have overlooked???

Cheers
Dave

[Horney]

Dude I have a compression tester if you want to troll up to basingstoke on sunday I can check it out for you.

Nick

[Conker]

Dude I have a compression tester if you want to troll up to basingstoke on sunday I can check it out for you.

Nick

Quality, cheers Nick, I'll see what other replies I get to my question first, then maybe take you up on your kind offer. If its more or less 90% defo the HG, I might just get cracking as I've got the rest of the week off to have a go - This will be my first "big job" on the Mk2 (bent valves here I come!!  )

[Horney]

Well let me know if you want it done, my mobile number is 07734 963525.

Nick

[JimR]

When my h/g went ir was leaking coolant and oil to atmosphere so a compression test showed it was all ok. It does sound like head gasket failure though, check thoroly(sp?) for coolant leaks from the flanges on the head, 30 mins is absurdly quick to be dumping the lot, i'm sure you'd notice white smoke at more thsn idle.,

[richard s]

there is a sniffer kit available that that i will try ro describe the best i can
it is like a turkey baster that you put a blue liquid in then stick in your expansion tank and pump and if the liquid turns green your head gasket is fooked
try a few garages to see if they have the kit and would do the test for you
or see if sealy tools do a online catalogue as im quite sure it was a sealy one i borrowed

[Mr Blue]

I have the EXACT same engine mate

You have a coolant leak but its not visible. Like mine...does your coolant vanish over night and sometimes get alot of air in the cooling system because of this

[Conker]

You have a coolant leak but its not visible. Like mine...does your coolant vanish over night and sometimes get alot of air in the cooling system because of this...

It doesn't vanish overnight, i.e. there are no puddles on the floor, but I do get air in the system. I was hoping it would be a leak, but that doesn't explain the white smoke coming out the exhaust.

For example, if I leave it idling on the drive, the ground behind the exhaust will be wet from water droplets being fired out of it.

[rombonie]

Hi guys

Mine was doing the exact same thing and i first thought it had to be the HG but it turned out to be a pipe failing. get the motor nice and hot with the coolant full. then have a good pull around on the hose's, ofcourse be mindfull of the fan it's going to cut in and out. Mine had a tiny split on the oil cooler feed pipes but they all needed replacing due to age really. It would only loss coolant at higher prolonged revs and wasn't leaving any signs of a leak anywhere but 20-30 miles and the coolant level light would be on.

Worth a look i reckon. good luck

[Conker]

Well, I've just spent around £150 on tools and parts to do "The Job". The HG is being replaced over the next few days on my drive.

Thanks for the suggestions, but I'm still convinced its a headgasket due to the white smoke out the exhaust. I've just taken it out for a run and its running great until it gets hot, then it gets spluttery (don't know if that relates to a headgasket failure ). The white smoke (prob steam?) is really bad when re-starting the car after its been left five minutes when hot e.g. when nipping into Halfords this morning.

Presumably when left standing, the cylinder pressure drops, allowing water ingress, which is then burnt off when the car is re-started. The car is also difficult to start when this happens. This would also support the symptom of a long run being nowhere near as bad on coolant use, as the cylinder pressure is high for much longer/consistent periods.


Wish me luck!