3.9i V8 Range Rover loosing coolant?

Hello all, I am new to the forum and thought I would join after recently picking up my 1992 Range Rover classic!

I love the beast but it has a unquenchable first for coolant and I was wondering if someone could give me some pointers?

Symptoms;

Engine always runs bang on the same temperature, just under half, no overheating issues.

Engine runs smooth and pulls well, I don't think it is down on power.

No hot or cold starting issues as such.

Coolant appears to disappear at random, sometimes barely using anything for days, sometimes it can use up to a litre in one journey!

Expansion bottle cap hisses when engine is turned off when warm, may hiss whilst running but I can't hear it. Coolant system pressurises but no more than any other car I have owned in the past, Coolant is not blowing out of the expansion bottle

No steam from the exhaust, only for a little while on a cold morning which I think is condensation

Coolant has a slight smell of fuel? Not sure, it requires a flush as its orange with rust. I will be giving it a service ASAP


I have read that these engines are prone to the blocks cracking and really hope this isn't the case, I haven't performed a compression test yet but the engine seems to spin over evenly on all cylinders.

Any help would be great as I am not sure where all of this coolant is going?!

Thanks,

Michael.

Welcome to LZ and the joys of owning a V8 Land Rover.

There are several ways that these motors like to expel their coolant. The worst case is a slipped cylinder liner or porous block. A lesser, but still serious culprit can be a faulty head gasket. After that it can be pin holes in the rad or any of the coolant lines or a bad expansion bottle or cap.

When refilling with coolant after a big loss or after a flush, these engines have a a habit of trapping air bubbles in the cooling lines that cause a blockage. Sometimes you think that the coolant level is good and then after a drive the trapped bubbles gets dislodged and the level drops making it appear as if you lost some.

Hello! Thank you for the welcome!

When I bought the the RR, it was low on coolant, the previous owner assured me that there was a "mystery leak" somewhere between the engine and the heater matrix, and supplied me with a spar P38 matrix which isn't the correct size, I can't smell any coolant in the cabin when the heaters are on, so don't think this was the case...

Unfortunately I spent so much time researching where to look on the body for rot I didn't discover the V8's flaws until I got home and started researching.

I am going to do an oil change as its due, and drain, flush and refill the coolant and see where it goes from there.

Is there anything which would help me distinguish between a bad head gasket, a porous block or a slipped liner?

I am confident on doing the head gaskets, but not sure if the RR is worth getting new liners put in

Thanks,

Michael.

It's worth checking the plugs to see if they are all the same, a clean plug can mean that cylinder is getting steam cleaned.
If you go as far as stripping the heads down it's worth inspecting the liners. There should be no lip between the liner & the deck of the block. If you can feel the slightest of ridges with your finger nail the chances are a liner has dropped.

Pic below of my old block.

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Only definitive way of testing the block is to have it pressure tested to check for coolant seeping from where the liner meets the block.

But check the obvious first, rad, waterpump, hoses etc

Thank you MartynV8!

I had a quick look over it today and topped up/bled the system using the bleeder on the radiator and the bleeder which sticks up from the block (a metal pipe I hadn't noticed before) and took it for a run. Let the engine warm up, stopped it for 5 mins and then fired it up, no smoke of any colour from the exhaust. Went to go get some petrol (getting very used to doing that with this tank) and noticed a puddle under the car after filling up, on closer inspection coolant was spilling out of the pressure cap even though when i undid the cap there was barely any pressure in the system, it looks like the threads on the cap and the expansion bottle are pretty chewed up, and there is coolant staining around the ridge half way along the bottle. So I am guessing this would be a good place to start, hadn't noticed any leaking until today but it had been raining pretty much every day since I bought it!

Thanks,

Michael.

Hi Michael,

Sounds positive if the expansion bottle is to blame, should be a easy cheap fix for a new bottle. Try a new one with a coolant flush & refill & see how you get on!

inlet manifold gasket also a culprit...cos you dont see the leak as it just sits under the manifold and dissapears as engine heats it up..cant think of the proper word for when water just dissappears like rain does on a hot road...(getting old....)

Thank you for the info everyone, it appears I am still loosing coolant, so I will give the inlet manifold gasket a go. May I ask, why is there a coolant supply to the intake manifold anyway?

Thanks,

Michael.

mikkey180 said:

May I ask, why is there a coolant supply to the intake manifold anyway?

Click to expand...

You may

It's not a supply to the inlet manifold as such. More of a junction.

The hot coolant comes out of both heads and meets in the manifold. It then leaves via 3 outlets;

> to the rad and thermostat
> to the interior heater matrix
> to the throttle body heater

The coolant temperature sensor is also located in the manifold.