Dave307

I'm thinking of a buying a 1988 RX-7 convertible and I noticed that the oil pressure ,when the car was warm, would drop down to almost zero on the gauge and then would go up to about 1/2 way on the gauge when driving. Is this a serious problem and can it be corrected easily? Apart from that the car runs fine.

daten

My 1990 gtu has done that since I got it, I assumed it was normal. I'm not sure if the pressure drops all the way down, but when at idle it is very low and when driving it goes up to around the middle.

Mombodogs

Did you by chance to make sure that there is in fact oil in it? I'm new to rotaries, but somewhere I read, oh yeah, up top in the thing that says read, oil level in a rotary, like any other engine, is somewhat important. No oil, no pressure, period! Good luck, hope it works out.

PEACE THE DOG

apreludem

mine does that too....i've been told that it would need a rebuilt soon but i'm not sure how serious of a problem this is..or if it's anything to be worried about.

felixwankel88

im amazed no one has responded with a good awnser to this yet, if you are geting decent oil pressure at running speeds, and no or all most no oil pressure at idle, you have a pinched or blown out front covor o ring, you need to pull the front cover and install a new one

apreludem

ah, thanks for the answer....i guess i have the same problem with OP.....i need to get the video on how to rebuild so i can start working on my baby =)

" Me and my car are both 16" haha that's awesome ! =)

TurboIIRyan

Um yeah, why don't you go and check the oil sender first? If there is a bad connection that will cause that. Also are you verifing oil pressure with the stock gauge? Get yourself a real mechanical gauge and then tell us the real numbers.

NZConvertible

A dirty or loose connection at the sender will cause funny readings, so you should check that. However even though my sensor's connection was clean and tight it still read lower than I was comfortable with. An aftermarket mechanical gauge proved the oil pressure was fine (~180kPa/26psi at idle). See if you can get it checked with another gauge.

felixwankel88

yes i never thoguht of cleaning the sendor, but i do know that the front cover 0 ring is a
weak link on many rx7s...

88 rex turboII

mine did that right after my rebuilt was put in and i was freaking out but turned out to be that the sending unit is great.but i still get 80+ at idle.

apreludem

mine at idle is like 5 or so...will have to check with a mechanical gauge before i jump to conclusions though

88 rex turboII

thats the best way you can find out with a mechanical gauge the stock one sucks.

Dave307

Thanks everyone for the replies and keep em coming . I'm feeling a little better. I did check the oil level and it was just under the full level so that isn't the problem. Got a question for Felixwankel. How big a job is it to pull the front cover and change the o-ring?

88 rex turboII

you gotta pull the motor off cuz once you pull the front cover off the oil pan gasket will tear and you gotta replace it. so your going to need a oil pan gasket,o-ring and the front cover gasket.

felixwankel88

wrong, it is a decent job, but there are a few ways to do it, 1 u can unboltt the motor mounts, jack up the tranny, remove the oil pan, remove front main bolt, removce the pulley, and go at it, or u can just unbolt the oil pain bolts to the front cover, pull it off, and RVT the dshitt outta it back on installation, if u have more questions just post in the thred, ill keep checkin

88 rex turboII

well if you want to do a nice job thats the way to do it.buy dont get me wrong you can RTV the crap outta it cause there's no pressure there but eventually ill leak.but it can be done

Juiceh

iTrader: (4)

I had the same thing happen to my 91 vert. at idle it was like 0-5 PSI under load it would get to about 30 PSI. I tested with a real gauge and it was in fact low PSI. Turned out my oil pump was failing. Got it replaced and now at idle its now about 30-45psi and at load its about 60+. Low Oil pressure is something you want to get fixed ASAP or you will start running into costly problems.

apreludem

mine gets normal oil when it's cold...makes sense since the oil is still cold and thick...once warm it drops in oil pressure cause the oil is now warm and thin...JUICEH did yours do this too? or did you have bad oil pressure even when the car was cold?

88 rex turboII

yeah mine does that too but when its warm already and im driving i get a 100 psi.

Juiceh

iTrader: (4)

No I had low pressure even when car was warmed up and idling and low when cold.

88 rex turboII

its gotta be the oil pump.so many yrs. with the stock one kinda wears it out huh?

Juiceh

iTrader: (4)

Yeah, I had assumed it was the oil pump from the start. After getting a new one the oil pressure was great. I know my engine thanks me for it!

88 rex turboII

yeah thats true.did you install it or you had somebody else do it?

Juiceh

iTrader: (4)

Had it done at a local performance shop a block away from where I work. I could have done it myself but I don't have time. I'm lucky as hell theres a shop down the block from work.

Icemark

No, that is wrong. Dead wrong.

It is more than likely the E-shaft thermo pellet has failed.

See with a pinched oil cover O ring (number one the motor must have been rebuilt or had the front cover off withing the last 6 months) the oil pressure at idle is normal, and goes up slight as RPMs raise, then drop back down as RPMs go even higher.

If the E-shaft thermo valve has failed or stuck, oil pressure works like normal except that it is 15-20 PSI down the whole RPM range.

And for his symptoms, you can pretty much rule out anything else than that, other than if he has a really messed up oil sender connection or a mis-alighned oil pressure gauge needle (both of which are pretty doubtfull).

I hope the guy didn't go out and waste a bunch of time and money pulling the front cover when a $15 part would have solved his problem.