Thread: 1988 3.5 f.i. loosing coolant

Well, have you checked underneath where the heads meet the block front and back? This is a common area of leaks and there should be coolant drool there. This means a new headgasket set.
Have you looked under the carpets in the front? the heater matrix is another common fail. But with 1litre you would be wading before long.

Another is just a radiator hose having a loose clip. The one at the bottom of the radiator on the RH side is a prime suspect.

I have never seen a cracked head on a RV8. RV8s rarely mix water and oil simple because there is only one water hole in each block at each end and none between cylinders.

Of course once you have ruled out external leaks you then get to the slipped sleeve syndrome.
Regards Philip A

I had almost exactly the same problem in a 92 RR, turns out it was a bottom heater hose with a pinhole leak that would open up when the engine was hot and up to speed ( on a run or something ), $20 buck hose and was fine after that.

Ray,

Originally Posted by Dizco

there is no apparent back pressure through the overflow when hot or cold and she does not yet overheat all....

Do you mean there is no pressure when you take the cap off? If so, there should be when hot and a cap not sealing may be your problem.

Hi there, first post!. Maybe similar to my problem in my 91 rrc, there is a small leak of cylinder pressure through the head gasket and into the cooling system, (which has been pressure tested and will hold 15 psi for well over an hour). The pressure builds up within the expansion tank and then this pressure build up is displaced by coolant which is then shooting out the top of the cap (the vdo one with the sensor). It loses the whole expansion tank which i think is around 3-4 litres on most driving, and sometimes after i have parked it and it cools down. Maybe a pressure test of your cooling system first, then if not that a compression test, and even pressure testing cylinders with air hose tapped into an old spark plug and check for bubbles in coolant. Thats what we did .

then if not that a compression test, and even pressure testing cylinders with air hose tapped into an old spark plug and check for bubbles in coolant. Thats what we did

AND? have you replaced the head gaskets and the problem has gone away?
If not you may have a slipped sleeve as this is a prime symptom. There are only two water holes in each side of the block in a RV8 (at each end) and usually gasket failure will force an external leak.
What is the compression reading of each cylinder?
Regard sPhilip A

we pressure tested all cylinders and all came around 150psi. And sorry i should have said we havent done the head gaskets yet but are pretty sure thats what it is.