Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Pmacca2000 on 21 July 2018, 18:14:53

Title: 2.5 V6 plastic cam cover
Post by: Pmacca2000 on 21 July 2018, 18:14:53
Has anyone on here had past experience of cam covers warping on the 2.5 V6?

Title: Re: 2.5 V6 plastic cam cover
Post by: danzigfan on 21 July 2018, 18:28:01
Yes....used one are risky to buy. They're all warped esp. the side with oil filler hole. Mine is having a really small leak on that side. Still have 2 spair pairs in garage but they are all slightly warped. I'm searching for vectra's alu cam covers but IF they appear the price is just over the top. I decided to live with that small leak which is BTW much smaller than it was when I bought the car. It was like it ran on steam not gasoline
Title: Re: 2.5 V6 plastic cam cover
Post by: BazaJT on 21 July 2018, 18:33:12
Not had a 2.5 so no,however they were warped on my 3L when I bought it,they were "bowed" on the outer edges.Bought a good used pair from a member on  here.I know the correct torque setting for the bolts is important but I do wonder if age and constant heating/cooling cycles don't have a hand in it too.
Title: Re: 2.5 V6 plastic cam cover
Post by: GastronomicKleptomaniac on 21 July 2018, 18:49:35
Not uncommon, it only takes one pillock to overtighten a few bolts.

Ali covers are an alternative, but could lead to failure of something more major, like a rear crank seal...!
Title: Re: 2.5 V6 plastic cam cover
Post by: Bigron on 21 July 2018, 20:35:45
Not uncommon, it only takes one pillock to overtighten a few bolts.

Ali covers are an alternative, but could lead to failure of something more major, like a rear crank seal...!

Why?

Ron.
Title: Re: 2.5 V6 plastic cam cover
Post by: BazaJT on 21 July 2018, 21:56:04
I believe the reasoning goes something like:Cam cover gaskets leak due to pressure build up if breathers aren't kept clear and they're the path of least resistance.Alloy covers somehow overcome this[less "give" than plastic ones?] and the next path of least resistance to the pressure then becomes the crank seals[particularly the rear one for some reason it seems].
Title: Re: 2.5 V6 plastic cam cover
Post by: Doctor Gollum on 21 July 2018, 22:26:27
The alloy covers don't warp, so can be bolted down to twenty billion lbft...

The plastic ones distort, badly, if over tightened and consequently leak. Alot.

That said, fit new plastic camcovers, torque them correctly and clean the breathers every 6-12 months and you should have no issues.

Fitting alloy covers is not a solution for regular breather cleaning and fitting them for reasons beyond cosmetic with inevitably result in leaks elsewhere, especially the crank.
Title: Re: 2.5 V6 plastic cam cover
Post by: Sir Tigger KC on 21 July 2018, 23:20:37
We had a long convoluted discussion a few years ago about the merits (or not) of fitting a DIY pressure relief valve on the cam covers.  So if the breathers did clog up, this 'valve' would blow before the gaskets.  :)
Title: Re: 2.5 V6 plastic cam cover
Post by: Pmacca2000 on 22 July 2018, 19:45:34
Is the breather easy to get to?
She’s only out for summer use these days
Title: Re: 2.5 V6 plastic cam cover
Post by: BazaJT on 22 July 2018, 21:08:08
The breather box is the awkward bit as it's at the rear of the engine on drivers side.There is a guide in maintenance section on cleaning breathers which explains all :y
Title: Re: 2.5 V6 plastic cam cover
Post by: deviator on 23 July 2018, 10:34:09
Makes mental note to look for metal covers in my collection of quality used parts.
Title: Re: 2.5 V6 plastic cam cover
Post by: STEMO on 23 July 2018, 12:48:54
Makes mental note to look for metal covers in my collection of quality used parts.
Bang them together, if they sound like mess tins, they're metal.  ;D
Title: Re: 2.5 V6 plastic cam cover
Post by: deviator on 23 July 2018, 13:15:38
Makes mental note to look for metal covers in my collection of quality used parts.
Bang them together, if they sound like mess tins, they're metal.  ;D
I don't think I kept any of the plastic ones, but I seem to remember having 2 or more sets, I was keeping some as spares!
Title: Re: 2.5 V6 plastic cam cover
Post by: cam.in.head on 23 July 2018, 19:14:03
We had a long convoluted discussion a few years ago about the merits (or not) of fitting a DIY pressure relief valve on the cam covers.  So if the breathers did clog up, this 'valve' would blow before the gaskets.  :)


Yes .a perfect solution no doubt. We all should keep our breathers clear but if neglected(even not intentionally)a way to release pressure before further damage is dine is a good idea. Mine has a small 5mm hole drilled in the filler tube with a blob of silicone over it. If the breathers ever block then hopefully the 'blob' will blow !.    Visually seen anytime bonnet is open
Title: Re: 2.5 V6 plastic cam cover
Post by: Tick Tock on 23 July 2018, 20:58:42
I've got my own opinions on GM plastic cam covers and 'experience' tells me the gaskets make no difference at all - that is cheap versus genuine. Torque them down at 6lb/ft as recommended, but age and engine mileage will always hold sway..... in other words if the engine has reached 6 figure mileage, then no matter what gaskets you use (or how clean your breather system is), oil leaks will be inevitable.

Recent events resulted in brand new GM plastic covers at £300 for the pair (which come with gaskets). A couple of months later I still run my finger along the seals and it comes out clean and oil free.

So in summary (and shoot me down in flames if you wish) plastic cam covers have a limited life span. Alloy covers may well last the course. Keep the breather system clean, and that will be the least of your worries, but rest assured, plastic covers do warp after a long period of time and are subject to hairline cracks, making the gaskets the least of your worries.... correct me if I'm wrong, just speaking from 20 years of experience with the X25XE engines.
Title: Re: 2.5 V6 plastic cam cover
Post by: Migv6 le Frog Fan on 23 July 2018, 21:08:04
Mine are 6 years / 180k miles old and are fine. Never had a problem with any of mine apart from changing gaskets on my first 2.5.
Always kept breathers nice and clean.
Title: Re: 2.5 V6 plastic cam cover
Post by: Pmacca2000 on 24 July 2018, 18:24:52
I think they’ve had a good run then as she was built in 1999 and as far as I know they are original.
The frustrating thing is the oil leak has just been found!
I can’t wait to get her back and hopefully oil leak free
Title: Re: 2.5 V6 plastic cam cover
Post by: Doctor Gollum on 24 July 2018, 19:14:19
You really should change your garage...  :-X