Thread: D2 V8 Coolant leak possibilies?

Take the car to a steep hill, fang it up the hill, stop and open the bonnet. If it has spewed coolant out of the reservoir your system is being pressurised by combustion gases. Otherwise lie underneath with a strong torch and loos at the back end of the head gaskets.

On a D1 I replaced head gaskets a few weeks ago and it still pressurised. So I shifted the coolant return from the rad top tank to a fitting screwed right into the top of the expansion tank. This way combustion bubbles don't force the top 100mm of coolant out of the rad each time you go out. Seemed to work OK.

There is oil seepage coming from the head gasket so I will replace them soon and get the heads skimmed. Once pulled I can then see where the problem lies.

FYI the coolant tank mod on the D1:

The v8 can get a coolant leak from the timing cover,painful.
You have to remove the timing cover which is basically the front of the motor and replace the gasket,( might as well change timing gear if needed while there) you can do all this with out removing the radiator. A common sign for this is coolant stain on sump.Hope you find a simpler cause.

Hi It'sNotWorthComplaining!,

Your loss of cooling fluid may be due to something less expensive than a blown head gasket. We also had a coolant leak after switching to OAT coolant on our Discovery II V8. The coolant was leaking from somewhere under the air-conditioning compressor, and flowing down the side of the engine and onto the sump. On tracing back the stained flow line of the red-orange marks of the OAT coolant, it at first looked like they originated from a major head gasket problem, but on further investigation, the cause was a crack in the plastic pipe coming from the throttle body de-icer. The plastic pipe had become brittle and snapped, and thus leaked coolant even though the crack was not visible until the pipe was moved. See the link to the thread http://www.aulro.com/afvb/discovery-...ant-pipes.html

Hence, testing the cooling system with a radiator pressure tester may be worth while to see if there is a pressure drop due to a leaking hose or pipe.

Usually, with a head gasket failure, you will have coolant in the engine oil, and oil in the cooling system. There also will be excessive steam and water coming out of the exhaust pipe when the engine is at operating temperature.

A simple test to determine the presence of water in the engine oil is to remove the oil filler cap, and if there is a white, milky sludge underneath it, there is definitely water in the oil. To locate the cylinder or cylinders concerned, simply remove the spark plugs. The plugs in the affected cylinders will look new and clean due to their being steamed cleaned by coolant in the oil.

Alternatively, if you suspect that a cylinder head gasket is leaking, you could test the cooling system fluid with a combustion block tester or a combustion leak tester to determine if there are exhaust gases in the cooling system.

LRT

Originally Posted by LRT

Hi It'sNotWorthComplaining!,

Your loss of cooling fluid may be due to something less expensive than a blown head gasket. We also had a coolant leak after switching to OAT coolant on our Discovery II V8. The coolant was leaking from somewhere under the air-conditioning compressor, and flowing down the side of the engine and onto the sump. On tracing back the stained flow line of the red-orange marks of the OAT coolant, it at first looked like they originated from a major head gasket problem, but on further investigation, the cause was a crack in the plastic pipe coming from the throttle body de-icer. The plastic pipe had become brittle and snapped, and thus leaked coolant even though the crack was not visible until the pipe was moved. See the link to the thread http://www.aulro.com/afvb/discovery-...ant-pipes.html

Hence, testing the cooling system with a radiator pressure tester may be worth while to see if there is a pressure drop due to a leaking hose or pipe.

Usually, with a head gasket failure, you will have coolant in the engine oil, and oil in the cooling system. There also will be excessive steam and water coming out of the exhaust pipe when the engine is at operating temperature.

A simple test to determine the presence of water in the engine oil is to remove the oil filler cap, and if there is a white, milky sludge underneath it, there is definitely water in the oil. To locate the cylinder or cylinders concerned, simply remove the spark plugs. The plugs in the affected cylinders will look new and clean due to their being steamed cleaned by coolant in the oil.

Alternatively, if you suspect that a cylinder head gasket is leaking, you could test the cooling system fluid with a combustion block tester or a combustion leak tester to determine if there are exhaust gases in the cooling system.

LRT

Thanks for the info, I don't have any plastic pipes going to the de- icer, only the one that fits along side of ther top of the radiator and it connects to the top of the rad, the other end goes to the expansion tank, There has been a weep coming from the rad end from under the clamp, I reckon some prior must have broken the small connection pipe coming from the rad as there isn't much to clamp the hose one.

I see you mention coolant stain under the power steering pump , mine had some stain there also. The hoses to the de-icer are rubber hose that run behind the a/c compressor, may be there is a nick in them , will have to pull it off and have a closer look.

Unless I'm losing some from a water pump retaining bolt? There was nothing in Rave to say the bolts need coating before fitting.
Any way can't do much this week as the disco is in the panel shop getting fixed after the rear ender it sustained.

Hi It'sNotWorthComplaining!,
Its worth checking for cracks in the plastic pipe right at the connection to the rubber hose. What a blow about the rear ender!
LRT

Have you remedied this issue yet? It sounds exactly like the problem I had with mine, which was as mentioned before, a timing case leak.

You don't want any coolant loss on these engines. Get it diagnosed ASAP!