Oil leak

wiz043 · Postby **wiz043** » Thu Feb 10, 2011 4:33 pm

My '99 MX5 has developed a small oil leak after a reasonably long trip of spirited driving.
It appears to be engine oil and seems to be coming from the 2 rubber grommets at the end of the accelerator cable leading up to the butterfly or under the butterfly body itself.
There is oil residue under the lower grommet and under the butterfly disc and the lower accelerator cable that is wrapped around it.
It then drips onto the black cables under the butterfly and the cable retainers to the left and 2 bolts under them.
The oil also gathers on the car body to the left and under the charcoal canister although it could be blowing back into this area.
Should there be any oil around the throttle body area to lubicate the butterfly mechanism ? Any ideas ?

93_Clubman · Postby **93_Clubman** » Fri Feb 11, 2011 3:53 pm

From looking at my NA8 & an NB8 throttle body, reckon it might be due to the PCV valve & hose from cam cover to intake manifold, which may be letting some oil residue through into intake manifold which is building up. Some throttle bodies can get gunked up, which is why they benefit from an occasional clean.

If not, it might be dripping previous lubrication of either the throttle cable or throttle butterfly - has the car been to a mechanic recently?

wiz043 · Postby **wiz043** » Tue Feb 15, 2011 11:15 am

Thanks for reply. The leak is not coming from the pipe into the intake manifold, it seems to be in the butterfly area.
It was serviced not long ago but I did not think that they would lubricate this area. Perhaps they filled the throttle cable behind the rubber grommets with oil somehow and after a long run the excess oil finds it's way around the butterfly disc and drips. Does that make sense ??

93_Clubman · Postby **93_Clubman** » Tue Feb 15, 2011 5:19 pm

wiz043 wrote:The leak is not coming from the pipe into the intake manifold, it seems to be in the butterfly area.
It was serviced not long ago but I did not think that they would lubricate this area. Perhaps they filled the throttle cable behind the rubber grommets with oil somehow and after a long run the excess oil finds it's way around the butterfly disc and drips. Does that make sense ??

Not saying it's coming directly from there - what I'm suggesting is that it's indirectly due to oil residue that some times escapes via the PCV valve & pipe into the intake manifold, & then if it builds up, runs down inside the manifold, to dip from the area above where you've seen oil residue gather.

Likewise, wouldn't expect them to lubricate that area, but it's possible at the moment in the absence of a definitive explanation.

wiz043 · Postby **wiz043** » Sun Mar 06, 2011 9:10 am

Re my '99 MX5----I have investigated this leak further and have come to the conclusion that it may be a power steering fluid leak because the p/s fluid level in the reservoir is very low and the steering 'groans' on full lock etc.

However when standing in front of the car the reservoir is on the right hand side and the leak is on the left hand side under the throttle body and charcoal canister area and subframe underneath.

Could anyone tell me if the p/s pump and/or pipes are in this area (charcoal canister side) as the a/c fan could be blowing oil around as well making it hard to trace. The leak isn't severe at this stage and only occurs when I check the area after a long drive.

project.r.racing · Postby **project.r.racing** » Sun Mar 06, 2011 1:34 pm

it would help your cause if you take a pic of said problem. then the guessing game for solutions can stop.

deviant · Postby **deviant** » Sun Mar 06, 2011 2:00 pm

Yep take a picture for us to look at.

It is not normal for a throttle to be lubricated. The sheathe is designed to allow the cable to move freely without an added lubricant. In fact it is recommended to not add any lubrication as it attracts dirt and can make the cable stick.

wiz043 · Postby **wiz043** » Sun Mar 06, 2011 2:10 pm

Oil appears to gather in this area (see attachment).
On throttle cable grommets and 2 bolts below and nearby black cables and retainers and blue metal area under charcoal canister and on subframe below. Are there any p/s pipes etc. in this area that attach to the steering rack or whatever that could possibly leak under pressure and blow fluid around?

Obviously I know little about the workings of the p/s and it is hard to see unless the car is on a hoist.

The problem may be something completely different but I just cannot see how there could be an oil leak in this area coz I have checked the obvious which is the rocker cover gasket and it is ok.

oil leak 1.JPG

Mr Morlock · Postby **Mr Morlock** » Sun Mar 06, 2011 2:22 pm

I think you diagnosed it- low p/s reservoir. Top it up / wipe excess oil where visible/ drive for a period say a week/ recheck and if the level has reduced....

wiz043 · Postby **wiz043** » Sun Mar 06, 2011 2:33 pm

Mr Morlock wrote:I think you diagnosed it- low p/s reservoir. Top it up / wipe excess oil where visible/ drive for a period say a week/ recheck and if the level has reduced....

Yeah---thanks, I am fairly sure the p/s fluid level has dropped over the last month or so but what I don't know is where the leak is as it doesn't appear to be at the pump end which is near the reservoir as far as I can determine.
The leak is on the opposite side.

Guran · Postby **Guran** » Sun Mar 06, 2011 7:40 pm

Hi John. The following diagram shows the locations where you need to check for power steering fluid leaks (noted by arrows). This schematic is for a LHD NA6, so some artistic license is required! You'll need to jack up the front so the wheels are free, and put it on stands. It'll be easier if you remove the undertray. Start the engine and let it idle. Turn the steering from lock to lock a few times, then hold at full lock in each direction to place the system under pressure. (not more than 15 seconds each). Check for leaks at the "arrowed" locations. If you find leaks, check and tighten the affected joint, or replace worn/damaged hoses as required.

IMG_1220 by Guran5, on Flickr

BTW, if you'd like to borrow a NA6 workshop manual, you're welcome to mine for a few days.

wiz043 · Postby **wiz043** » Sun Mar 06, 2011 8:10 pm

Thanks Bryan---I'll give it a go. I have been trying to find a diagram like this on the 'net and the NB setup is probably similar.

I brilliantly printed out a mirror image of your diagram so it related to RH drive.

Mr Morlock · Postby **Mr Morlock** » Sun Mar 06, 2011 9:12 pm

don't any of the repair manuals show it. A leak may occur at any joint and as someone else pointed out - the best way to examine is on a hoist The net can be an excellent way of wasting time. This is really simple stuff.

wiz043 · Postby **wiz043** » Sun Mar 06, 2011 9:54 pm

Mr Morlock wrote:don't any of the repair manuals show it. A leak may occur at any joint and as someone else pointed out - the best way to examine is on a hoist The net can be an excellent way of wasting time. This is really simple stuff.

Yeah---thats right, but if you don't know what you are looking at the 'net is a handy tool to explain it to you. I have now downloaded the free complete repair manual for my model and saved it as there are too many pages to print it out.