Rocker cover gaskets Again!

Post by **Alan8086** » Sun Oct 14, 2018 6:14 pm

Hi - having replaced both rocker cover gaskets twice in the 3 months I've owned my Probe GT, seems I must do it again!

It's the rear one so off with the inlet manifold! I have smoke coming from just to the left of the clutch master cylinder.

What do I have to do to keep the rocker gasket sealed for more than a few weeks at a time?

I keep reaching a cliff edge with this car - really I need a car that is reliable just to do a 2 mile round trip to work and back and trustworthy when on occasion I go take my mum out somewhere - a drive to Cheshire.

I've replaced the clutch, 2 slave cylinders and two sets of rocker cover gaskets.

Is it possible to get These cars to run reliably and dependably for a length of time? Mine drives beautifully, plenty of power etc, starts and stops perfectly well. Are they a labor of love?

Post by **Micron** » Sun Oct 14, 2018 7:04 pm

Hi,

Did you use a RTV sealant when you replaced the gaskets?
Did you tighten the cover correctly, and not over tighten it?
Maybe it might be an idea to replace the rocker cover as well, as it might e out of alinement?

As for can you get these running smoothly, in a word "yes"

Post by **mojo98** » Sun Oct 14, 2018 7:33 pm

I`ll add to micron`s comment`s
RTV sealant to both faces,
and did you leave the car for at least 24hrs before running it,
I`ve done mine (front and back) and on 2 of the probe`s and have been fine, fastened them to the right pressure,
yes run fine

, but like most cars on the road these day`s have issues,

Post by **Alan8086** » Sun Oct 14, 2018 9:42 pm

I did apply RTV to the cylinder head surface. Also applied it to the groove in the rocker cover where the gasket goes. Do you also apply RTV to the gasket itself once it is located in the rocker cover?

I bought a low torque torque wrench - tightened up the bolts to correct torq. The torque suggested is a range - I lightened it up to just short of the max.

Oh, yes I left it overnight and a bit more for the RTV to cure.

First attempt at the gaskets failed due to not having a sutable torque wrench, that was a practice run. Second time I got it right - until now

Post by **Sunfly** » Sun Oct 14, 2018 11:44 pm

You've got something going on there mate! Speaking from a purely engineering point of view (as I've never lifted a cover on this engine), and with everyone else's excellent advice in mind... I'd be checking the covers for flatness!

O ring seals are incompressible but they will deform under pressure and on a seal of about 4mm diameter, about 0.015" or 0.4mm is about right for an o-ring to be deformed to create a good seal. However, 15 thou is not a lot of distortion for a thin walled alloy casting if its been over-tightened or not fitted properly in the past. Your problem may be that the cover is flat no longer and the seal not being compressed enough.

Another possibility is a crack! Its crude, but a good check for cracks is to immerse the head in paraffin for ten minutes then dry it with an airline or paper towels before dusting it with talc or chalk. If you've got a crack it will show a damp line where the paraffin in the crack gets sucked out by the talc.

Good luck!

Post by **jrh** » Mon Oct 15, 2018 9:57 am

Labour of love ?
Yes, absolutely. Cost any work you do at 'garage rates' and you will soon exceed the resale value of the car.
As other posts, check for flatness of both surfaces, head and cover.
If the cover is 'banana-shaped', even a 'little' , between the holding down cap nuts ,it cannot be made to seal as designed.
If it is not perfect the O ring cannot do its job.
Originally, the RTV was just to plug any gaps at each corner.
RTV anywhere else introduces 'problems'.

Post by **Alan8086** » Mon Oct 15, 2018 2:28 pm

jrh wrote: ↑
Mon Oct 15, 2018 9:57 am
Labour of love ?
Yes, absolutely. Cost any work you do at 'garage rates' and you will soon exceed the resale value of the car.
As other posts, check for flatness of both surfaces, head and cover.
If the cover is 'banana-shaped', even a 'little' , between the holding down cap nuts ,it cannot be made to seal as designed.
If it is not perfect the O ring cannot do its job.
Originally, the RTV was just to plug any gaps at each corner.
RTV anywhere else introduces 'problems'.

So When new, RTV was'nt used except in the corners, where the manual recommends? So it was meant to seal with (almost) no RTV?

They certainly engineered a weak point into getting the rocker covers to seal?! The heads are at a tilt, the oil pools over the lip of the cam head casting, so its going to be up over the line of the gasket seal?

Oh well, for about 2 hours i had decided to sell this car - didnt last long when i considered the alternatives and hassle!

I do love the look and drive of the Probe. I could buy another Saab 9-3 but then have endless EGR/DPF related problems. I coud buy something sensible, small, fuel economic, petrol, hybrid - but it would be like driving a retirement home!

No, I'll stick with it for now. I'm getting faster at lifting the manifold off now!

Thanks all for your comments

Post by **fuerte** » Mon Oct 15, 2018 4:51 pm

I am in similiar boat as mine in for rear and front gaskets again.But at least mine lasted 3 years.I think my last garage only put sealant on corners.may be an idea to aak garage to let it stand 24 hours.But he isnt sarting it to wednesday.
So I will pivk it up friday.
This garage hasnt done my rocker cover gaskets before but we will see.has done other stuff.
Anyway at least have coutesy car.And being laid up with chest infection great cure for worry.lol.

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Rocker cover gaskets Again!

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