Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

Hi just wondering what's the common problems to look out for on 2l 8v cav engines ? Cheers

If you're thinking of buying an 8V cavalier then the engine will be the least of your worries.

Over the years both the 20SEH and the 20NE/C20NE have built up a reputation for being extremely reliable.

They are very strong engines with not much to go wrong.

The most common fault seems to be the ICV valve so be sure to check that.

Other than that just do the usual engine checks like if there is any blue smoke on start-up, any suspicious looking deposits in the oil or water and check for any overheating problems.

Mechanically speaking - the big 8 valve engines are pretty much bullet proof.
(C18NZ, C20NE, 20NE and 20SEH).

I suppose it is down to how well they are looked after...
200,000 miles is easily achievable. Even with only standard maintenance.
A full service every 12 months should be enough to keep the engine running happily.

A head gasket should be happy for well over 100,000 miles.

Cam cover gaskets weep for fun, and high mileage engines will probably need new rear crankshaft bearing seals and camshaft bearing seals.

Keep the breather system clean and you shouldn't suffer too much with clagged up icv's and oiled up throttle bodies.

The weak spots with any Cavalier are corrosion...nothing to do with the engine.

My original NE had a superb fault or 3....but not usual common or garden stuff like the usual problems that affect anything -

used to take ages to drain the hot oil out of it....
used to idle strange, too high basically. well weird. never sussed it til the end

Thing pulled like the proverbial though....Seem to remember the oil light flickering at the traffic lights in Farnham on the way to work. revved it and it went out. took it a little easy that am, just gave it death 95% of the time, instead of the usual.....Got to work ok, fired it up to go home, oil light stayed on. turned it off, got recovered. Clearly oil was not occurring where it should have been. Took sump off to find a valve thrust pad stuck in the oil strainer. Had been there ages and had polished the inside of the sump to a near mirror and itself quite extensively.
Very strange. So what was going on? the thrust pad disc thingy was new, had never seen a valve stem, no round mark on it at all, we deduced it had been dropped down the rear oilway ages ago or at manufacture, (tried it, it fitted!) it must have slid around the sump for 20 odd years, finally found the small recess on the oil strainer, got wedged in, rattled about a lot, the 2 sharp edges of the pad had finally worn into the mesh that morning on the way to work, bits of the stainless steel mesh had gone up the oil pipe and round the pump, it was a mess! smashed the pump gears badly. The bearings had suffered too and they were well past the bearing material and into the brass coloured backing. it still ran well with a new pump and filter/clean out. ran it for 2 more years till chapter 2 occurred -

It always used a bit of coolant and seemed to pressurize the header tank a tad. went ok for ages, just topped it up once a week.
When we took the NE out when I decided to go XE power, I took the head off. Head was cracked on #1 between the valves and coolant had been squirting into the cylinder, it had steam cleaned the place! This had done something strange to the spark plug in it's final 6 months of life and the ceramic had come off and smashed about the combustion chamber and utterly wrecked the head with little bits stuck in it, piston was very unwell and the bits had scraped some well tasty grooves up the bore. Still went like stink, didn't use oil as such, maybe a tiny bit, pulled like a train still that morning, even with the part assembled XE engine in the boot.

So, as the man says, the 2.0 8V are just about unburstable! even when something weird occurs.

I replaced my C18NZ with a C20NE well after 200,000 mile mark because the oil light came on at idle.
Went off again above 1000 rpm.
Never was 100% sure whether my big end bearings were finally getting worn, or if the oil sender was fubar'd.

The engine is as good as the previous owner.

Robsey wrote:Mechanically speaking - the big 8 valve engines are pretty much bullet proof.
(C18NZ, C20NE, 20NE and 20SEH).

C16NZ2 is also in that category.

2.0 8v ant that strong ive killed one. VERY easily.


Was towing a mates korean heap to the scrap yard when the oil light popped on under load. Let of the pedal and it went out. and thought its the oil pressure sensor (had a 1.4 16v astra previously and did the same, changed the sensor and away you go). Anyway dropped the car off collected the cash and away i went. Got to junction 10 of the m42 came off and had a chav in a corsa being a dick at the lights so i thought i would show him up. Lights went green and i floored it. then went a tap, tap, tap then a bang and a cloud of blue smoke. turned out me towing the mates car had killed the main engine bearings as we found out after taking the sump off and finding it full bits of metal and small ball bearings in amongst the oil.

5853moore wrote:2.0 8v ant that strong ive killed one. VERY easily.


Was towing a mates korean heap to the scrap yard when the oil light popped on under load. Let of the pedal and it went out. and thought its the oil pressure sensor (had a 1.4 16v astra previously and did the same, changed the sensor and away you go). Anyway dropped the car off collected the cash and away i went. Got to junction 10 of the m42 came off and had a chav in a corsa being a dick at the lights so i thought i would show him up. Lights went green and i floored it. then went a tap, tap, tap then a bang and a cloud of blue smoke. turned out me towing the mates car had killed the main engine bearings as we found out after taking the sump off and finding it full bits of metal and small ball bearings in amongst the oil.

Any engine with no oil pumping around will last very long regardless of strength. In your case the oil light flashing means very little or no pressure. Oil pumps like any other pump are subject to wear and failing destroying crank bearings, crank etc
Doesn't mean to say the 8v is weak, just means you were ignorant to the oil pump failing believing it was the sender

Cant agree more, the 20SEH in my old sri took a beating and never once complained, did 143,000 on original headgasket, clutch, all bearings, never needed a thing. I ended up scrapping it due to a rotten body in the end, wish id re-shelled it to this day. Miss that car !

All I can say is that my old C18NZ had done roughly 30.000 miles in my ownership, service parts were replaced as needed, but being an automatic, I was giving it the beans when on a run, never complained on cold starts, started at -5 before, no rattles, no smoke or funny smells, ran extremely smoothly at 112000 ish. Unfortunately the rest of the car needed attention quite badly, otherwise I'd still have kept it. I taught myself mechanical work from that engine, don't ask how but it just taught me a hell of a lot. Great engines, although not as torquey as the 2 liter lumps.

I have towed a very old Range Rover in my C18NZ..
Over humped bridges and alsorts for about 2 miles across Stockport.

Car didn't complain once, in fact I could barely feel the 2 ton lump behind me.
I had to keep reminding myself, that I was towing, and that it wasn't some tw@t getting up my back bumper in his Chelsea Tractor.

If you're talking about a P35, they are definitely not chelsea tractors... I love those old beasts, would snap one up if the money was right. Not the most economical run-about, which is why I'd definitely get the V8.

Lol....These are near enough indestructible...

Had mine now 4 years and all I have done to it bar standard servicing is add a K&N panel filter and better exhaust and she flys, I am well known for having a lead right foot amongst my friends and the Cav gets driven hard fairly frequently..

It has some annoying stuff like the ICV is cr*p so I put a Omega V6 one on mine which works perfectly and the noisey fuel injection which sounds like the tappets going mental otherwise all mine has done is kill its sensors due to them being old and cooked its head gasket which I got a garage to sort out for me although people say they are easy to do..

Does leak oil on a regular basis but also manages on average about 375 miles to a full tank with combined town and motorway driving, the C20NE is also pretty quick off the line and my has seen a tad more than the speed limit on the motorway

For a older car she is an absolute legend, never let me down yet..

My ne has 205000 miles and runs sweet has just passed the not as well. Only real problems I've had is the icv clogging but a oil catch tank has sorted that and the slight oil and water leak I'm yet to have the time to find. Main problem I have at the minute is finding new fuel lines to replace the rotten ones from the tank

Rage wrote:My ne has 205000 miles and runs sweet has just passed the not as well. Only real problems I've had is the icv clogging but a oil catch tank has sorted that and the slight oil and water leak I'm yet to have the time to find. Main problem I have at the minute is finding new fuel lines to replace the rotten ones from the tank

You won't be able to find new lines. You'll have to have some made up for you from copper pipe.

Troy made some up for me a few years ago.

Same here -
Troy did a stirling job of making some from cunifer.
Nice and shiny

But that's what I can't find. Only stuff I can find is 3ft long and I don't want a load of joins lol

Buy a roll of it, it's about 30quid.
Frost also sell it

Never heard of frost before just googled it and found the fuel pipe cheers troy. Now I just need the cash. Can anyone help with that?

Rage wrote:Never heard of frost before just googled it and found the fuel pipe cheers troy. Now I just need the cash. Can anyone help with that?

I've got some cash that I can sell to you lol

Yep - Frost Auto-restorations in Rochdale.

Some good toys and chemicals to play with.

5853moore wrote:2.0 8v ain't that strong I've killed one. VERY easily.


Was towing a mates korean heap to the scrap yard when the oil light popped on under load. ...Anyway dropped the car off ... had a chav in a corsa being a dick at the lights so i thought i would show him up. Lights went green and i floored it. then went a tap, tap, tap then a bang and a cloud of blue smoke...

So... umm.. not THAT easily then...

2.0 8v engines have a well-deserved reputation for being bullet-proof and with regular service intervals and good maintenance and repair can last for ever

Totally agree the 2.0 8v is the best engine, power, great economy and longevity. My first 2.0 G plate saloon went like stink, only ever done basic maintenance, and got 59.9 MPG - yes you read that right - on a run down the spine of the country. As is the case with most cavys the bodywork succumbed and had to scrap it. Sad day running the last of the fuel out of the pipes when I was stripping it all down for bits. Drained tank then ran engine till it emptied the lines, it seemed to keep spluttering back to life as if it didn't want to go!

Just to add how realiable these are!

Not once has it not started in 4 years and last week due to time off and a injury she barely moved bar a trip over to see Andrei then sat for 6 days and turned the key and fired, never worry about it not doing so tbh