RX8 head gasket

[JulesB]

Just gone to top the oil up on the Mazda, dipstick is covered in a foamy residue, checked the roof of the oil cap and there was a few drops of water...

These seem like symptons of a head gasket.. Expensive fix on the Mazda?

[Robb F]

JulesB said:

Just gone to top the oil up on the Mazda, dipstick is covered in a foamy residue, checked the roof of the oil cap and there was a few drops of water...

These seem like symptons of a head gasket.. Expensive fix on the Mazda?

Very cheap to replace the head gasket on an RX-8

Apparently the cause of this is condensation mixing with the oil, and nothing to worry about. Go to the http://mazdarotaryclub.com/ and have a look

[JulesB]

Robb F said:

Very cheap to replace the head gasket on an RX-8

I'm praying this is not sarcasm!

[Robb F]

JulesB said:

I'm praying this is not sarcasm!

Your engine doesn't have a head gasket, as there is no head. I edited with some more useful advice.

[Lee_sec]

Jules the RX8 doenst have a head gasket - the creamy stuff around the dipstick is fine - they all do it...

[JulesB]

Don't I feel like a clown! Cheers for the insight chaps

Had the car for 4 months now and its the first time i've seen it!

[marcosgt]

Lee_sec said:

Jules the RX8 doenst have a head gasket - the creamy stuff around the dipstick is fine - they all do it...

I think there's a later dipstick design that's less prone to it, but it's pretty common and just affects the tube, not the oil inside the engine.

Worrying, but not problematic like it would be on a piston engine and Lee's right there's no head and no gasket

M.

[JulesB]

Cheers for clearing it up guys - I was thnking I was about to run into a big bill!

[wolves_wanderer]

JulesB said:

Don't I feel like a clown! Cheers for the insight chaps

Had the car for 4 months now and its the first time i've seen it!

Only tends to happen in cold weather.

[The Flying Ox]

The cure, as with most things rotary, is to take it out for a drive and rev its tits off.

[JulesB]

I did do that today... Had a problem with idling when I got back though!

[Mave]

Lee_sec said:

Jules the RX8 doenst have a head gasket - the creamy stuff around the dipstick is fine - they all do it...

Doesn't it have a seal between the main body (where the coolant passageways go) and the end plates?

[Robb F]

Mave said:

Doesn't it have a seal between the main body (where the coolant passageways go) and the end plates?

It sure does.

[Mave]

Robb F said:

Mave said:

Doesn't it have a seal between the main body (where the coolant passageways go) and the end plates?

It sure does.

That's what I thought. So it doesn't have a cyclinder head gasket, but it does have a side gasket which, if it fails, causes the same problems as a CHG failure in a piston engined car?

[Robb F]

Mave said:

That's what I thought. So it doesn't have a cyclinder head gasket, but it does have a side gasket which, if it fails, causes the same problems as a CHG failure in a piston engined car?

The oil is in the centre and the water jacket around the outside, so no.

Edited by Robb F on Sunday 16th December 21:06

[Mave]

Robb F said:

Mave said:

That's what I thought. So it doesn't have a cyclinder head gasket, but it does have a side gasket which, if it fails, causes the same problems as a CHG failure in a piston engined car?

The oil is in the centre and the water jacket around the outside, so no.

Edited by Robb F on Sunday 16th December 21:06

Ah, OK, so no oil galleries going to the outer / end plates, everything fed from the centre?

[Robb F]

Mave said:

Ah, OK, so no oil galleries going to the outer / end plates, everything fed from the centre?

Yup. Because the crank is in the centre that's where all the oil is needed. There is an oil injector in each rotor housing that lubricates the trochoid surface and the outside is just a water jacket.

[Mave]

Robb F said:

Yup. Because the crank is in the centre that's where all the oil is needed. There is an oil injector in each rotor housing that lubricates the trochoid surface and the outside is just a water jacket.

Cool, thanks.

[JontyR]

Mave said:

Robb F said:

Mave said:

That's what I thought. So it doesn't have a cyclinder head gasket, but it does have a side gasket which, if it fails, causes the same problems as a CHG failure in a piston engined car?

The oil is in the centre and the water jacket around the outside, so no.

Edited by Robb F on Sunday 16th December 21:06

Ah, OK, so no oil galleries going to the outer / end plates, everything fed from the centre?

The oil comes in at the rear where the sandwich plate is. It is then split to equally be sent along the top gallery above the spark plugs, then down the front plate to lubricate the front bearing. The other split goes straight down the back of the rear plate to feed the rear bearing. Oil is also sent through the e-shaft to oil the centre bearing.

I am disappointed though that it took 4 posts to come clean!! That could have gone on a few pages first!! We could be changing cams...valves...and sorting piston knock is a real problem!!

[BrettMRC]

If the water seals fail (generally only seen on engines that are at least 10 years old, or have been sat for ages) then you get a pressurized water system and champagne bubbles etc.