Thread: Discovery 1 V8 3.9 1999

I have 2 disco 1's with 3.9 V8 engines.

Please don't waste your time with any detailed fault checking if you have overheated the engine.
First thing to do is a compression test. seriously, they are well known to not do well if overheated.
Ok, my second disco over heated, same result, almost started, but not, long story short, it blew the head gasket. well, that happened due to cylinder liner no. 8 dropped. replaced liner, engine was rebuilt, but did it again within days. It is now my donor disco. sad, because it is in much better condition than my other one.

If the compression checks out OK, go buy a lottery ticket, you are very lucky. Then proceed to run ignition checks etc.

How did it overheat? if top radiator hose went, it sprays coolant all over the distributor, leads and ignition module, coil etc. I would start there by cleaning all components, at least give them time to dry out.

Originally Posted by Ronski

Ok, my second disco over heated, same result, almost started, but not, long story short, it blew the head gasket. well, that happened due to cylinder liner no. 8 dropped. replaced liner, engine was rebuilt, but did it again within days.

Would you recommend anybody rebuilding to use top hat liners?

Yes, most reputable Rover V8 engine rebuilders in UK and US always use top hat liners.
RPI Engineering in UK
Atlantic British etc. etc.
But, if the alloy between has failed it makes no difference. water can still creep up.

Disco 1 V8's are very cheap these days, around or under $2,000. hard to justify spending 3 times that to rebuild the engine properly.

My daily routine now is, park on a clean section of floor, well, it is a land rover, but among all the usual drips of oil, Before starting, look for signs of coolant leak. sometimes too late when out on the highway.

D1 V8 starting issues. The first thing I would be checking is the ignition module. There is heaps of info on this site about them.

Originally Posted by Ronski

I have 2 disco 1's with 3.9 V8 engines.

Please don't waste your time with any detailed fault checking if you have overheated the engine.
First thing to do is a compression test. seriously, they are well known to not do well if overheated.
Ok, my second disco over heated, same result, almost started, but not, long story short, it blew the head gasket. well, that happened due to cylinder liner no. 8 dropped. replaced liner, engine was rebuilt, but did it again within days. It is now my donor disco. sad, because it is in much better condition than my other one.

If the compression checks out OK, go buy a lottery ticket, you are very lucky. Then proceed to run ignition checks etc.

How did it overheat? if top radiator hose went, it sprays coolant all over the distributor, leads and ignition module, coil etc. I would start there by cleaning all components, at least give them time to dry out.

Thank you for feedback,

No coolant leak, no white smoke, nothing in the oil, no leaks anywhere in the engine, all hoses intact. The engine bay was hot and I did not risk driving the car, As I was in RACQ with free towing I just got the Disco delivered back home so I didn't take the risk. I'm assuming the car overheated as the expansion tank was under huge pressure and 3/4 full of coolant.

I need to get the Disco started to warm up the engine before doing a compression test : (

Originally Posted by Andrew67

I need to get the Disco started to warm up the engine before doing a compression test : (

No , you don't , you can still tell what is going on from the readings with a cold engine

the expansion tank was under huge pressure

So, question is, from where did this huge increase in pressure originate.

It is a simple check, remove all plugs full throttle open and a few cranks each. worth the piece of mind.

Your experience with your Disco exactly mirrors what happened to my 3.9.
Engine over heated, cooling system over pressurized and coolant went everywhere with nothing to indicate what caused the problem. How ever mine could be restarted. After this incident it ran perfectly and I drove it for another 5000kms without further incident. Then it began missing....oops. Turned out the original incident was caused by a leaking head gasket between two of the cylinders which had resealed itself and this had began leaking again.

The cause of the original incident was a very hot day with the a/c on, working the car on a bush track with an unknown to me failed cooling fan hub and the head gasket gave way at a weak point.