My P38a eats coolant ...

[willem]

G'day guys,

99 4.0 P38 180 000 kms; motor has 70 000 kms.

It keeps using coolant, and I don't know where its going.

I have done the heater O rings, and it is, as far as I can see, not leaking into the inside of the car any longer.

The motor has just 70 000 kms on it and is in A1 condition. As far as I can see there are no leaks on the motor. Not even any oil leaks, but that's another matter!

The LPG system was new 12 months ago, and I have traced the hoses around and I can see no leaks or signs of leaks.

Occasionally there is a small showing - a couple of drops - of coolant on the carport floor. Lining it up it is from the back of the motor, just to the left of centre. I can see no source of the leak. It is nowhere near enough to account for the coolant loss.

Otherwise the car is all good. No overheating or any other such issues.

And it still eats coolant - about a half a litre every three or four days.

Its got me stumped! Any ideas? The only one I have is perhaps an internal leak in the LPG converter?

Willem

[81stubee]

There is a little l shaped hose that goes into the bottom of the manifold at the front. I'm not sure whether the Thor manifold had this hose or not, but mine was leaking and it was very hard to tell. You may need to stick a mirror down there, and look back up at the base of the manifold. I now have it easy as I have a Endoscope camera on a flexible hose, so looking into tight places is a sinch.

Stu

[Hoges]

There is a little l shaped hose that goes into the bottom of the manifold at the front. I'm not sure whether the Thor manifold had this hose or not, but mine was leaking and it was very hard to tell. You may need to stick a mirror down there, and look back up at the base of the manifold. I now have it easy as I have a Endoscope camera on a flexible hose, so looking into tight places is a sinch.
Stu

Do you accept medicare card? :eek: :angel::wasntme:

[wayneg]

One of the leaks I had on my Thor was a small hose running across the top of the engine behind the aircon compressor and alternator. The leak was so small that with the heat of the engine it evaporated and never reached the ground. It took ages to trace, the smell of the coolant gave the area away. Had to remove the Compressor and alternator to change the small hose as no way could I get at it.

[PhilipA]

about a half a litre every three or four days.

You would certainly notice if it was an external leak.

My picks would be
Internal leak in gas converter.( there was some discussion on this a while ago) . Is it a "gas ring" or vapour injection?
Slipped sleeve. Nuff said
Regards Philip A

[Keithy P38]

Nuff said summs that one up!!

Also might pay to check the tell-tale on your water pump. Its a little hole on the left hand side of the pump that dribbles when your pump is cactus! The leak on mine dripped down the block, along the length of the sump and ended up dripping from around where the sump plug sits!

Its hard to see without a torch and some good spotting, but if it's leaking, you'll notice those first few drips within a minute of the car starting up from cold! I caught mine in the act luckily!

Cheers
Keithy

[willem]

The next installment in the coolant saga ...

I've isolated - by-passed - the heater and the LPG system, and it still leaks coolant. Its coming from the back of the motor in the middle. It is running in a steady stream down the outside of both sides of the bell housing and dripping steadily from there.

As far as I know it can only come fro the join between the inlet manifold and the valley cover/ cylinder head area, where the coolant flows into the inlet manifold. But I'm not totally convinced.

Does anyone have experience with this that can enlighten me? It's getting a bit frustrating! Otherwise I may have to start stripping it all down. :(

Thanks

Willem

[BigJon]

The first Adelaide trip I did with the Disco 3.9 in my Rangie resulted in a tow truck trip home. It was pouring coolant out at the back of the engine and it was running down the bellhousing. I couldn't see exactly where it was leaking even with a mirror.

I came to the conclusion it was either the intake manifold gasket or a head gasket, so I started stripping it down. While undoing the intake manifold bolts I found the two rear bolts on the drivers side were only finger tight. Obviously this was the cause of the leak.

The coolant doesn't pass from the block into the heads at the rear, so I guess it ends up being a slightly high pressure area in the cooling system and prone to leaking.

[Rupert Prior]

the most probable cause is the valley gasket, but there are a few things it can be as they leak onto the valley gasket and run out from the back of the motor, throttle heater plate and its associated pipe work, coolant temp sensor, top hose or its steel extension tube leaking or is rusted through, heater outlet O ring behind alternator, the ends of the head gaskets.

[PhilipA]

This thread is from the 27/07/2010.
I would think it has been fixed long ago and the original poster has not bothered to tell the forum what the outcome was.

Regards Philip A

[Junosi]

Mine leaked from that location - it was the valley gasket. Not too difficult to replace.

[willem]

This thread is from the 27/07/2010.
I would think it has been fixed long ago and the original poster has not bothered to tell the forum what the outcome was.

Regards Philip A

Philip,

I was the original poster ... and it's still not fixed. I fixed the heater O rings. That stopped the leaking in the car. didn't stop the coolant loss though. So I have been slowly working thru the issues as I have had time. As my post today indicates I have isolated everything that could be an issue and that is why my question now. I've run out of options ...

It seems tho that the comments here are leading me to the same conclusion that I was coming to ... the valley cover/ inlet manifold connection.

As soon as I have resolved it I'll let you know.

Thanks

Willem

[rofosixone]

did you change your radator overflow cap in your p38a , on my holden it was leaking water (with added steam) from radiator (not overflow as different set up ) than i got a $10 new rad cap and fixed the water loss and ran cooler again instantly / in my p38a i change the overflow bottle cap every 100,000 km automatically so can not say had that prob in that , but in holden did that and that fixed / worked .
can only try if you havent done that option yet on yours .

[PhilipA]

I was the original poster ... and it's still not fixed. I fixed the heater O rings.

Wow, I apologise.
Have you tried just tightening the rear bolts to see if it made a difference?
IFAIR you can reach them without removing the plenum, if it is not a Thor.

BTW although I understand there is a risk of delamination, to me the valley gaskets with the black stuff on them are far superior at sealing than the tin ones. I have fitted a black one to mine.
Regards Philip A

[willem]

Hmmm. This has got me perplexed. From all the drawings and pics I have been able to see there is no coolant passage from the heads to the inlet manifold. As far as I can see there are not coolant passages in the inlet manifold at all. So it follows that the leak cannot come from the valley cover gasket at all. Please correct me if I am wrong with this.

But it is still coming from the back of the engine - running down both sides of the outside of the bell housing, coming from on top of the bell housing. Remember that the heater and the gas system have been bypassed so the leak is not coming from them.

This is not a small leak - it is a steady drip drip drip and will leak half a litre every day or so.

Any ideas and suggestions welcome.

Willem

[Scouse]

As far as I can see there are not coolant passages in the inlet manifold at all. So it follows that the leak cannot come from the valley cover gasket at all. Please correct me if I am wrong with this.

I'll correct you.

Does your top radiator hose not go to the inlet manifold?

:)

[willem]

I'll correct you.

Does your top radiator hose not go to the inlet manifold?

:)

Fair comment Scouse. Thanks.

But does that invalidate my point about there being no connection at the valley cover interface?

Willem

[bee utey]

Fair comment Scouse. Thanks.

But does that invalidate my point about there being no connection at the valley cover interface?

Willem

There are water ports through both ends of the inlet manifold gasket, both sides. Generally only the front 2 are used, the other two allow the fitting of each head to the other bank by rotating the head lengthwise. Then the front ports become the back ports.

http://www.aulro.com/afvb/attachment.php?attachmentid=35811&stc=1&d=1305170757

And yes, they do leak, sometimes copiously.

[ytt105]

I had coolant leaking from my gearbox a year ago!!

Turned out it was the valley gasket at the rear of the engine. A new gasket and it was all fixed.

When I removed the inlet manifold a couple of the rear bolts were not as tight as the others. That might have been all I needed to do, but by then I was deep enough in to continue with the valley gasket replacement.

[adm333]

Does anybody have any photos they could post to point out which are the two boltsat the rear of the inlet manifold that could be loose ?

I am following this thread with interest...

Thanks

Dave

[PhilipA]

The last 2 manifold bolts. Look at bee utye's photo, and they are the opposite end ones to the 2 RH bolts ( that go in the holes) in the photo. If you feel along the rear of the manifold flange you can easily find them.
Regards Philip A

[PaulP38a]

Here are a couple of pics to add to bee utey's pic and PhilipA's comments:

Top view with inlet manifold removed, rear of engine at right, bolt holes in question at top right.
http://paulp38a.com/gallery/d/227-1/RR-Engine-093.JPG

And another pic while putting it back together, bolts in question to left of injector.
http://paulp38a.com/gallery/d/1983-1/RR-Engine-269.jpg

Hope this helps.

Cheers, Paul.

[willem]

Well, I finally fixed the problem. I took off the top half of the inlet manifold, and went to take off the bottom half. But I found that all of them were loose! Some by three quarters of a turn. So I tightened them all, reassembled everything, and it hasn't leaked a drop since.

Thanks for all the help and ideas.

Willem.