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Rover 800 825 KV6 MLS Head Gaskets

Rover 800 825 KV6 MLS Head Gaskets
Rover 800 825 KV6 MLS Head Gaskets

Car: 1999 Rover 800 825 V6 Coupe (no.2)

Colour: Zircon Silver

There is a rumour that the head gaskets fitted to all Rover 800 KV6 engines are likely to pop at anytime! Is this likely, well unfortunately, yes, it would seem so!

The earliest KV6 engines fitted to Rover 825's from '95-'97 also seemed to be very susceptible to piston liner problems too!

It seems that a lot of the cars that had the early engines had them replaced under warranty, some even receiving two or three replacement engines, as this was easier and cheaper than trying to repair them! The bad engines were just swapped out!

Although the piston liner problems seemed to be sorted in the next KV6's i.e. from '97-'99, it seems the head gasket problems have remained!

It is not known which cars got which engines in 1997.

The head gaskets seem to often go between the 50,000 - 60,000 mile mark, but can go at almost any time, even within a few thousand miles of replacement!

The very last of the KV6 engines fitted in the Rover 800's had a Multi Layer Steel (MLS), Head Gasket fitted. This makes the chances of the head gaskets popping fall right down. Very few of the 800's were fitted with this modification, which was introduced just prior to the KV6 engine making it's way into the Rover 75 range.

Although the KV6 Engines fitted with the MLS head gaskets in the 800, do seem to be the bulletproof ones, this does not mean the KV6's in the Rover 75's are great! Some reports on the 75's seem to suggest that the Rover 75 KV6's have VIS valve problems as well as liner problems!

I have not heard of any probs from a Rover 800 '99er fitted with the MLS gaskets and I would say owning one of these is better than having a Rover 75 KV6 as it does seem to be the most reliable of them all.

With my first KV6. I was almost convinced that because the car been serviced every 3000 miles from new and had just 35k miles on the clock when I bought it, that mine would be ok, but at 42k one of my head gaskets went (and the other was on it's way out). I had no prior coolant loss or temperature/running problems until the moment the gaskets went.

Most sellers and buyers are genuinely not aware of any KV6 problems unless they have had them.

This is a pic from when the Gaskets in my KV6 Coupe (No.1) went; (see; Rover 800 825 KV6 Head Gasket Failure)

It seems a tow truck came as standard with every Rover 800 equipped with a KV6 engine!

On the gaskets in the KV6 Coupe (no.1) above the bead was cooked around the rings. Almost all the 800's have this standard type of elastomeric gasket fitted, and yes it is quite a big job to change them, which unfortunately these days just means many of these cars are now being scrapped, as the cost having a garage fit replacements, is now usually more than the car is worth in most cases.

I replaced mine, and refitted the same type, so in a few years I expect to be doing them again!
If you have the heads skimmed you can fit the multi-layer type gaskets that were fitted to the last of the 800's and to the Rover 75's.
These do not need replacing once you fit them and should make the engines bulletproof.
Rover 75 engines themselves can not just be fitted straight in an 800 though, so that is not really an option (and the VIS valves on the 75's are a big problem anyway so the best KV6 engines are the late 800 ones, once fitted with multi-layer gaskets).

If you are lucky, you may have bought one of the very few late cars that was fitted with Multi-layer Type Head gaskets rather than the elastomer beaded type above.

These tend to be on V-reg Rover 800's with later chassis numbers (get the last six digits of your chassis number from front windscreen for a clue to when the car was built). (We have had '99 cars with chassis numbers ending in 257??? through to 260??? numbers). Those with the MLS head gaskets fitted all seem to be 259??? and 260??? from reports so far, but this does not mean all 259??? and 260??? had them fitted. You have to check the gaskets themselves to find out!

A 259*** car could be late enough in the run to have the newer type gaskets already fitted, but nobody knows when they started to fit them or how many got them, and I think like all other Rovers any changes in engines hit the production lines randomly as engines were just fitted from any piles of new and old stock at random, rather than from certain dates/chassis onwards, so it's impossible to know, the only way is to check.

You can tell which are fitted without taking the engine apart. Remove the engine cover, and If you look down from the engine lifting loop with a torch you should just be able to see the corner of the gasket. The front one is over the other side below a green connector.

The pics below show a multi layer steel (MLS) type head gasket that was fitted to the second of my Rover 800 KV6 coupes. This was a 1999 V-reg which from all accounts had never been changed, and so was one of those end of line cars. It had a 260??? chassis number. The MLS Gaskets will be dark in colour and will have the small rivet ring in the corner. The normal/single layer elastomeric gaskets will just be silver in colour (or will be rusty/rusted) without the rivet ring.

Rover 800 825 KV6 MLS Head Gaskets

Rover 800 825 KV6 MLS Head Gaskets

Sorry if it's difficult to see where my photos were taken from, (they were difficult to take!) The rear one is down from the engine lifting hook, normally the sparkplug leads would be in the photo too (you can see the clip for them in my photo)!

Whichever head gaskets you do have always stick to at least semi-synthetic engine oil, but if you can afford it go for fully synthetic oils. We like Magnetec and Halfords own amongst others, and make sure you use a good or recommended antifreeze such as Comma XStream G30.

If you have just checked your car to find it does have the MLS gaskets fitted, then I reckon you are smiling right now!


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