Valve cover and VTEC gaskets seeping oil?

[LeftyF]

I have a 1991 NSX manual I bought from a dealer in California last year. They listed that the Valve cover and VTEC gaskets were seeping oil, but we figured it just needed new gaskets so I didn't sweat it too much. Oddly they listed these gaskets as having been replaced a month before I bought the car, so though we're going to do that again, that may not be the problem. I've also had the cylinders compression tested and they all came up to spec, so I don't think it's related to blow back.

I had seen a comment from another owner here that they had the same issue on a '91 they bought from California, and they had to change something (I think valve related) to reverse a California smog tune. If anyone knows how to confirm this or any other ideas I'd much appreciate it.

Thanks in advance!

Fred

 

[DOHC5]

Check your PCV. Sits on top of the front valve cover. Pull it out shake it, should sound like you’re shaking a can of spray paint. If it’s clogged you won’t hear anything. Just replace it. Easy fix. Not sure this is your issue but it’d be the first thing I’d check.

 

[MotorMouth93]

I would clean any oil off and then see what's actually leaking before you go replacing gaskets.

 

[LeftyF]

I would clean any oil off and then see what's actually leaking before you go replacing gaskets.'

Yes, this was done by the previous mechanic but we'll be doing that again. I like the PCV valve test as well. I think I'll just change it out anyway as it's a simple change and can't hurt assuming the replacement is not DOA.

 

[Old Guy]

Clean and inspect to confirm the source of the oil leak. Replacing the PCV valve on a 1991 would never be a bad idea; but, do the PCV valve test described in the service manual to confirm that there is not some other blockage / problem in the PCV system. Are there any previous owner modifications to the engine compartment or is everything stock? Is the leakage on both the front and back covers which would further support a crankcase pressure problem or just one cover?

The valve cover gaskets and timing cover gaskets are 'fiddly' to install. If the new gaskets were poorly installed they could be leakers and sometimes they will leak around the seal on the retaining bolts. There is also a plug high up on the block (or the head - can't remember the details) that can leak oil which some owners have mistaken for a valve cover leak. That is why it is important to clean, dry and inspect to confirm that the oil is actually emerging from the valve cover seam (get your inspection mirror out). No point in repairing somethin that isn't broken. Can't comment on the Vtec gasket because I have not gone there. Rockauto sells a Mahle complete valve cover gasket kit (front and back) for a nice price.

Something to consider - when was the timing belt replaced? If its fairly recent then proceed as planned. If the timing belt is due you might want to plan for a gasket fix at the same time as you do the timing belt. No point in opening up all that stuff twice.

 

[LeftyF]

Clean and inspect to confirm the source of the oil leak. Replacing the PCV valve on a 1991 would never be a bad idea; but, do the PCV valve test described in the service manual to confirm that there is not some other blockage / problem in the PCV system. Are there any previous owner modifications to the engine compartment or is everything stock? Is the leakage on both the front and back covers which would further support a crankcase pressure problem or just one cover?

The valve cover gaskets and timing cover gaskets are 'fiddly' to install. If the new gaskets were poorly installed they could be leakers and sometimes they will leak around the seal on the retaining bolts. There is also a plug high up on the block (or the head - can't remember the details) that can leak oil which some owners have mistaken for a valve cover leak. That is why it is important to clean, dry and inspect to confirm that the oil is actually emerging from the valve cover seam (get your inspection mirror out). No point in repairing somethin that isn't broken. Can't comment on the Vtec gasket because I have not gone there. Rockauto sells a Mahle complete valve cover gasket kit (front and back) for a nice price.

Something to consider - when was the timing belt replaced? If its fairly recent then proceed as planned. If the timing belt is due you might want to plan for a gasket fix at the same time as you do the timing belt. No point in opening up all that stuff twice.

Thanks for all the helpful advice. The timing belt was done last year before I took delivery, and that's been confirmed by my mechanic. Both of the valve covers are seeping oil. I'd like to think this was due to the last mechanic installing these incorrectly, but as they were done right before I bought the car, I'm assuming the original gaskets were also seeping oil. The car is stock except for a Science of Speed clutch that was done when the gaskets were done.

Thanks again!

 

[LeftyF]

PS - if anyone knows who might have an OEM PCV replacement that would be great. All I seem to be able to find are aftermarket.

Thanks again for the help

 

[LeftyF]

Clean and inspect to confirm the source of the oil leak. Replacing the PCV valve on a 1991 would never be a bad idea; but, do the PCV valve test described in the service manual to confirm that there is not some other blockage / problem in the PCV system. Are there any previous owner modifications to the engine compartment or is everything stock? Is the leakage on both the front and back covers which would further support a crankcase pressure problem or just one cover?

The valve cover gaskets and timing cover gaskets are 'fiddly' to install. If the new gaskets were poorly installed they could be leakers and sometimes they will leak around the seal on the retaining bolts. There is also a plug high up on the block (or the head - can't remember the details) that can leak oil which some owners have mistaken for a valve cover leak. That is why it is important to clean, dry and inspect to confirm that the oil is actually emerging from the valve cover seam (get your inspection mirror out). No point in repairing somethin that isn't broken. Can't comment on the Vtec gasket because I have not gone there. Rockauto sells a Mahle complete valve cover gasket kit (front and back) for a nice price.

Something to consider - when was the timing belt replaced? If its fairly recent then proceed as planned. If the timing belt is due you might want to plan for a gasket fix at the same time as you do the timing belt. No point in opening up all that stuff twice.

I found an OEM PCV valve, so as soon as I get the car out I'll have them replace the valve, test the system and see if that sorts it.
Fingers crossed and I'll report back when we have a result.

 

[Honcho]

I found an OEM PCV valve, so as soon as I get the car out I'll have them replace the valve, test the system and see if that sorts it.
Fingers crossed and I'll report back when we have a result.

Replacing the PCV is a good idea, but I'd echo @MotorMouth93 here and say you should clean off the area and figure out what's actually leaking. Are you sure it's the valve covers? Cam caps, VTEC gaskets and the oil pressure sender can all create drips on the engine block that look like they're coming from the valve covers. Although, it's almost always the valve covers because no one installs them correctly anymore.

 

[LeftyF]

Replacing the PCV is a good idea, but I'd echo @MotorMouth93 here and say you should clean off the area and figure out what's actually leaking. Are you sure it's the valve covers? Cam caps, VTEC gaskets and the oil pressure sender can all create drips on the engine block that look like they're coming from the valve covers. Although, it's almost always the valve covers because no one installs them correctly anymore.

That's what my mechanic said as well. They're going to do the test of the PCV system, replace the valve and replace the valve cover and VTEC gaskets correctly with OEM parts. They'll then clean the block and watch to see if the issue persists, and if so determine where the oil is coming from. Fingers crossed!

 

[LeftyF]

I'm able to find OEM valve cover gaskets for the NA1, but I can't seem to work out what to order for the upper and lower VTEC seals. Anyone have part numbers and / or a line on where to find them?

Thanks again for all the great assistance

 

[asylum]

15825-PR3-005 + 36172-PR3-005 before something like mid '94.
15825-P08-005 + 36172-P08-005 after.

 

[LeftyF]

15825-PR3-005 + 36172-PR3-005 before something like mid '94.
15825-P08-005 + 36172-P08-005 after.

Perfect - thank you!

 

[Honcho]

Perfect - thank you!

Remember the most important thing is to clean the mating surface with acetone. There can't be any oil or grit there or you will have a weeping oil leak in a few months.

Also, make sure your mechanic follows the torque specs for the valve cover nuts. Most techs crank them down way to tight and squish the gasket, causing leaks. It's only like 7 or 8 lb/ft.

 

[LeftyF]

Yea, he's got a lot of experience with this engine from his own car (and a ton of Honda repairs). He said exactly the same thing, I. E. the last mechanic may have just not done the job to spec and that's why it's seeping. We'll know as soon as the rest of my parts get here from Japan.

Fingers crossed!

 

[LeftyF]

The issue was resolved with the VTEC gasket. It seems they replaced the gasket with an aftermarket part that failed before shipping the car to me. I've driven it for a week up in the higher RPMs with no leaks, so this seems to be sorted. Hope this helps someone else!

 

[Old Guy]

Happiness is a garage floor with no oil spots (or other fluid spots).

 

[LeftyF]

Happiness is a garage floor with no oil spots (or other fluid spots).

We leave cardboard under our cars in our storage area, then play "name that stain" in the spring ;-)

 

[FlopShot]

Yea, he's got a lot of experience with this engine from his own car (and a ton of Honda repairs). He said exactly the same thing, I. E. the last mechanic may have just not done the job to spec and that's why it's seeping. We'll know as soon as the rest of my parts get here from Japan.

Fingers crossed!

I recently had both valve cover gaskets and the VTEC solenoid gasket replaced with the kits from SOS. Those kits didn't work very well and still had oil seep. My mechanic got another set of gaskets from his Acura contact and those worked fine. Same technician did the install so can't say that tech workmanship/knowledge was a variable. So maybe I just got old stock from SOS that already rotted? Anyway, point of my post is that previous mechanic might have just gotten bad (but correct) replacement parts like I did.

 

[LeftyF]

I recently had both valve cover gaskets and the VTEC solenoid gasket replaced with the kits from SOS. Those kits didn't work very well and still had oil seep. My mechanic got another set of gaskets from his Acura contact and those worked fine. Same technician did the install so can't say that tech workmanship/knowledge was a variable. So maybe I just got old stock from SOS that already rotted? Anyway, point of my post is that previous mechanic might have just gotten bad (but correct) replacement parts like I did.

Could be, but given other work that he did I’m not ruling it out!