jbherri2

iTrader: (1)

I drive my RX-7 at least once a week, assuming fair weather. When I'm not driving it, it stays in the garage. I took these photos after the car had been sitting in the garage for a couple of days. This is the second time I've found a mystery leak under the car. All fluids appear to be topped off. What is is?

The picture showing the stuff on the ground is on the passenger side of the car. Ignore the ugly tennis shoes. I looked under the car, but didn't see any apparent dripping. The leak appears to start somewhere between the transmission and engine. At least, if I'm looking at the floor of the garage, the puddle appears to start there. But, I don't see any evidence of a leak along the engine, the oil pan, etc. Thoughts?

And....maybe this should be in combination with my earlier post asking about oil pressure verification. I've got a lot to learn about the car. 78,xxx original miles, all original. Well, nearly. I did have to replace a headlight.

KansasCityREPU

iTrader: (9)

Check your oil metering pump and lines on the passenger side.

jbherri2

iTrader: (1)

Okay, so I took a gander this evening. All around the MOP/OMP looks nice and dry. The lines appear to be as I'd expect them to be. However, there seems to be some rod or something that is right near the MOP/OMP. It seems like it should connect to something under the carb, but it's all loose and flops around. I tried to take a picture w/ my phone, but it's no-goodski.

Additionally, the top of the engine, beneath all of that carb stuff looks wet. I was planning to take the cold-start coolant tank off and block off the line, but the wet stuff on my garage floor really loooks like oil, so I'm not sure this is related.

Thoughts?

LizardFC

iTrader: (1)

That metal rod is supposed to be attached to the throttle linkage on the carb. It activates the oil metering pump, so it's important. The cotter pin probably fell out or was removed. Easy fix.

The wetness under the carb is probably the typical intake manifold coolant o-ring leak. Fixing it requires removing the intake manifold and replacing the gasket and o-rings. I'd also check the coolant lines that run along the firewall.

Your oil leak... if it's coming from between the engine and transmission, then it could be the rear main seal. Or even a drain plug on the transmission. The best way to tell the difference between trans oil and engine oil is the smell... trans oil stinks! It could also just be pooling back there from an oil line on the engine, maybe at the pressure sender.

DerrickS

Another area to check would be the oil cooler o-rings.

t_g_farrell

iTrader: (1)

Is that a manual or auto tranny?

DivinDriver

iTrader: (15)

Hard to judge from a picture, but it looks too thin to be manual gear oil... and auto trans oil is usually reddish in color. Most likely engine oil... or REALLY dirty brake/clutch fluid.

As mentioned previously, smell is a good diagnostic, as is the feel of the liquid rubbed between two fingers. Brake/clutch fluid has a very different feel and smell to it than oil, as do gear lube, antifreeze, AC condensate.

Get the front end up where you can crawl under with a light, & remember that fluid can 'travel' along a seam or the top of a structural part (cross member, frame lip, etc) and drip a fair distance from the actual leak source.

jbherri2

iTrader: (1)

Sorry, should have been clear.
It's a manual.
1985 S model, all original, 78,xxx miles.

dankekong

iTrader: (2)

connect that rod ASAP!

jbherri2

iTrader: (1)

Well, I have more questions. I'm full of questions and I don't provide many answers!

Anywho....
The rod/shaft thingy that goes from the carb to the MOP/OMP is connected on the carb end (the top). But, on the lower end, where it connects to the MOP/OMP, it just slides up and down, but doesn't appear to move the pump at all. It looks bent to me, but I've never looked at one before. Remember I'm a total noob!

I can put my hand under the end of the connecting rod thingy and just bouce it up and down without moving the pump at all.

Any thoughts? Am I even sure what I'm doing?

thanks!!

Here's a link to the big fat photo....

gerald m

If you look close you will see a hole in the actuator rod not thingy about half way up from the washer hanging at the end of the rod . you should end up with a washer and small cotter pin on each side of the OMP lever . So remove the old washer and cotter pin that is there , pull the actuator rod out of the OMP lever , when you have the rod pulled out slide a cotter pin through the top hole then slide a washer up the rod to the cotter pin ,, slide the actuator rod back through the OMP lever slide another washer up the rod and insert another cotter pin in the bottom hole , Bend the cotter pins a BIT so they don't fall out and that should do it . So you end up with a washer and cotter pin on each side of the OMP lever . you might need to take the top of the rod off the carb to have enough movement to do the job. It looks like the OMP is a full open where it sits . you should be able to push the lever down by hand to make the job easier . not sure if there is a spring involved or not check things here Foxed.ca - Mazda RX-7 Manuals All the Factory Service Manuals are at this link . Remember no more thingy OK . I know pictures are not easy at first to do but try to downsize so your not all over the place although it is a very nice clear picture . Hope this helps Gerald m.

bumpstart

s3 type oil water heat exchanger has several o rings that often suffer and shrink with the heat cycling.. also sometimes on the oil passage dowel between the plates and housing , check here


also check the other ends of the OMP small lines to the carb are happy .. and that the little lines are not the source of oil or puddle

as for the OMP rod.. the OMP itself is stuck in full load position.. but should not be stiff and should return by itself to the low position.. some have a grub screw and nut to set minimum adjust , sometimes over adjusted

the rod itself should have several holes to move the washer and split pin to also adjust the max position

methinks the OMP itself may need overhaul.. very easy to do with a handful of o rings . somewhere i have a repair post ups with all the sizes

DivinDriver

iTrader: (15)

Yep, that OMP is stuck fully "open."

jbherri2

iTrader: (1)

Bringing this back from the (nearly) dead.

I slid a tray under the car and have kept it there for a week or two. Whenever I drive it, I put the tray back. So, once again, I've driven the car and then a couple of days later, I find this mystery puddle. It's a rather small amount. I'd thought maybe it was the sub-zero system. I disconnected it two or three weeks ago. So, I've eliminated that, plus this stuff is clearly not any sort of coolant. Is this clutch fluid? Brake fluid? Oil?

I'm currently running pre-mix until I determine the OMP is okay. (A shout-out to Ray there!)

So, what think ye?

Oh, it's a manual. 1985 RX-7s. And, I'm a little color challenged so I'm not 100% on what I'm looking at. The stuff feels like oil, but that doesn't make it oil, correct?

DivinDriver

iTrader: (15)

Does it feel thick and oily, or real thin, between your fingers?

How does it compare to the fluids you see in your brake reservoir, clutch reservoir, or on your dipstick?

Does it have a distinct odor to it?

With that color, it could almost even be gasoline that ran down an oily surface.

jbherri2

iTrader: (1)

Long time, no response. Sorry. Been nutty at work lately. I'm hoping to work on the car this week. Found a repeat of the puddle last night when I walked in the garage. Huge puddle, same color. It does feel oily, but it doesn't have any real odor to it. I have noob questions regarding the above (scary!):
BumpStart says: "s3 type oil water heat exchanger has several o rings that often suffer and shrink with the heat cycling.. also sometimes on the oil passage dowel between the plates and housing , check here" Any specifics? Where exactly am I looking? Thanks.

RotaryEvolution

iTrader: (30)

does the coolant in the radiator look rusty? if not then it probably isn't coolant.

looks like fuel from a leaky carb base gasket to me.

as for the OMP rod, it looks like someone bent the end of the rod so that the OMP is stuck fully open to inject more oil.

if it was clutch or brake fluid your reservoirs would be about dry by now.

jbherri2

iTrader: (1)

does the coolant in the radiator look rusty? if not then it probably isn't coolant.
-->The coolant looks like I'd expect it to. I know the PO changed it yearly.

looks like fuel from a leaky carb base gasket to me.
--> I thought about that, but it has no fuel smell to it at all.

as for the OMP rod, it looks like someone bent the end of the rod so that the OMP is stuck fully open to inject more oil.
--> I've got a new OMP and rod that I need to install. I've been running premix ever since I discovered the OMP situation. I hope to do the install this weekend, but things have been busy at work lately. Life happens. =)

if it was clutch or brake fluid your reservoirs would be about dry by now.
-->I thought about that, too. Actually, this was one of my earlier thoughts, but both reservoirs are holding fluid and do not appear to be dropping.

Additional question, do our cars have a vent valve on the transmission? Could that be what I'm seeing?

ray green

iTrader: (14)

Try mixing some of that stuff that's leaking out with an equal volume of water in a small glass container.

If it's gas or oil, it will separate into two phases, with the clearer water on the bottom.

If it's coolant or brake fluid, it will dissolve into one dirty phase (and like RE said, if it's brake fluid or even coolant you should notice the fluid levels dropping in your clutch or brake master cylinder or in the radiator).

Most likely it's oil, with the primary candidates being:

1) the OMP and/or connecting lines (oil could be all over the place if it's leaking from the lines and getting blown by the fan).

2) the beehive oil cooler O rings (there are two of them positioned where the beehive fastens to the pedestal; look for lots of oil below the beehive and all over the starter)

3) the oil pan gasket (oil will only be down low on the engine)

4) like DD said, could be a fuel leak washing oil from the outside of the engine down into the pan, but this would be accompanied by an obvious strong gasoline smell.

5) since you brought it up, maybe it is transmission oil. If so, it should be obvious that the oil is dripping from under the transmission, not forward in the engine compartment.

I'm betting on the OMP lines, probably either a crack in the lines or a weak connection at the base of the carb. (But check that tranny out too!)

RotaryEvolution

iTrader: (30)

if it's gas it will also light with a match.

hopefully not like a fuse.

jbherri2

iTrader: (1)

Note to self...no matches in the garage.

diabolical1

iTrader: (3)

don't rule out gear oil just yet. i have a mystery leak on the Gen II right now that appears quite similar to yours - seems to be coming from somewhere near the engine-transmission junction and runs quite a trail rearward. i'd noticed it leaving spots in the driveway for months now, but i had it in the garage for about 2 weeks recently and after pushing it back out, i was able to get a good sample from the garage floor. i definitely detected traces of gear oil when i smelled it (just not as strong).

i figured it's pointless trying to confirm by pulling the flywheel inspection plates, so i plan to drop the tranny whenever i can make the time to do so. front seal maybe?

MIKE-P-28

iTrader: (1)

Got 3 doing this at the same time!

jbherri2

iTrader: (1)

And the saga continues.
I finally crawled under the car this evening. It's been up on ramps in the garage since Saturday, but tonight is the first time I've had a chance to do anything. I took off the cover that connects to the front air dam, thinking it would give me a better view of the OMP. As you recall, I suspected the OMP to be the source of my leak. It would appear that is not the case.

I checked around the oil cooler, and it all looks good.

So then I thought maybe it was the transmission. But again, my thinking was wrong. The transmission appears to be nice and dry on the outside. While under the car, I get a nice fat drop of oil in my ear. (Better than my eye, I suppose!)

Recall that my car is all stock. 12a (S model). Around the exhaust appears all wet and oily. I can see that the oil pan, along the back and the passenger side, is rather oily. When I look closely, I can see what appears to be water mixed with the dripping oil where it gathers on the oil pan bolts. The car has been in the garage for days so I know that it's not from the rain. The car actually hasn't seen rain since I've owned it (six or seven months now). The leak appears to originate around where the exhaust header meets the engine, but that does not make sense to me.

I did think maybe it was just the oil pan gasket. Actually, that was starting to be my hope, but it appears to come from above it.

Any thoughts?

And the bit about the water that appears to be mixed in slightly...should I be worried? When I ran my finger along where the oil had accumulated, I could tell that there was a bit of water present.

diabolical1

iTrader: (3)

1. cross your fingers
2. pull the exhaust manifold
3. turn the engine by hand (while cold)