loosing coolant help!

[Dobbslc]

KZN185 . 3.0 I've been loosing coolant lately but can't find a leak anywhere. I have removed the rear heater pipes as they looked rusty but that hasn't helped. I've been under and over the engine & rad with torch but can't se anything no stains etc. It starts with only a bit of smoke which goes once hot it run ok and temp gauge stays just under half way. No mixed water or oil & clean red coolant .
I hope its not the head but has anyone got anymore thoughts on this?
I thought all my cooling problems had gone with the Vauxhall Frontera!

[Surfer Ross]

If it isn't leaking, its going out the exhaust ie; cracked head. My 3rd gen 3.0 never leaked a drop and didn't mix oil/coolant and it was cracked between the valves on every cylinder.

The steam/smoke on a cold engine is a good telltale.

Start the engine from cold with the radiator cap off. If bubbles/frothing are present in the radiator filler when you start the engine, the head is cracked.

[NiftyNev]

Pressure test cooling system.

Nev

[Bogus]

Like Nev said, pressure test it. It could be a small leak somewhere that opens up at temp and just evaporates, or blows away without leaving stains/evidence.
Is yours an Auto? have you checked your auto box level recently, Its not filling up and turning pink is it?

[Dobbslc]

I've checked oil levels and all looked ok with no strawberry milkshake, no bubbles in the rad etc.
I'm going to have another good look round tonight if I can.
If it's the head what sort of cost's am I looking at for parts etc? I'll do the work myself but what's the best option for a replacement head new, used, recon?

[Sparkie67]

Nice thought on that one about the auto box level. I have same problem of water vanishing. Can't see any visible leaks, no mixing with engine oil though my oil consumption has increased lately.
What's the best way to pressure test cooling system please.

[Dobbslc]

I bought a cooling system pressure tester off ebay for about £40 you might need an adapter for the rad cap though.
As an update the truck is still using a small amount of coolent but starts and runs well so I'm leaving it alone for now.
I'm like my boss on this one, if he ignores the problem then it doesn't exist!

[Sparkie67]

oil / water mix.

Hi

Sorry to jump in and tag a long on this post, just saves starting a new one on same subject.

Just done the sniff test on mine. All clear. And just to make sure, I sniffed the exhaust and the colour changed. To make doubly sure did it again at radiator for about 10 mins. Nothing....
Checked trans oil, all ok, no pinky milkshake in there, but does need changing.

Anyways, took oil cap off and guess what, start of a build up in cap and a lot of vapour coming from filler. Wasn't like that before, the water leak is not massive.

Obviously the head will have to come off, but are the heads prone to cracking between oil / water channels, or am I lucky and it's just the gasket thats gone.

Just recently it has also started with lots of blue smoke and at certain revs a small misfire. Also until warm it does make a bit of a pinking popping noise, could that be water boiling off in oil?

Many thanks
Andy

[Dobbslc]

Going on what has been said on here in the past I would say it's the head that's gone as those who have lifted the head usually find cracks.
I've left mine alone as it runs fine and only uses a small amount of coolent, saying that it'll probably go on the way to Cornwall sometime!

[Sparkie67]

I is not a happy bunny.

Had the spare head checked for square and pressure to day. Failed......cracks in 2 of the cylinders between oil and water.

So much for buying a spare head that was promised to be good.