Hi guys,
I had been looking to buy a 3rd Gen RX-7 and found what I thought was the perfect one. A 1993 with only 48,000 km’s on it (29800 miles).

I traveled the 5 hours to get to this dealership to test drive it. I did all the checks that I read to do and everything looked good. Started it and let it get the temp up and again everything looked good. Went for a drive and it drove very smooth, good power, second turbo engaged good. No smoke at all out of the tail pipes. Engine temp was always good.

Went back into the dealership where my friend hopped into the drivers seat to take it for a drive to see if I missed anything. 10 minutes later they pull in and while the turbos cool down (car idling) I decide to take some pictures. 5 Minutes later the sales man backs the car up in its parking spot and shuts the car off. We talk for a couple of minutes and am just about to go inside to sign when my friend looks on the ground and notices a puddle of engine coolant on the ground. It was dripping from the front right (passenger) side and looked to be maybe the overflow but it was just too hard to see where it was coming from for sure. I went in the car and put the key in to see if the car was overheating but the Temp gauge showed that it was not overheating at all. I started the car and let it sit for a few minutes and the temp gauge did not indicate overheating and it didn’t look like it was spewing out anymore coolant. This was a good amount of coolant (I would say at least one cup worth) that leaked onto the ground. It was late in the day and the dealership had no mechanics left there so they couldn’t put it on the hoist for us to look at where it was coming from. So I basically went home disappointed not wanting to take any chances. He said he would call me on Monday to tell me where the car had leaked the coolant from but I am not prepared to take their word for it since it can be easy for them to tell me it was just a loose hose clamp or something.

From my knowledge of cars the only time coolant will leak is if it over heats and comes out of the overflow, if a hose cracks or comes loose, or a gasket goes (usually from overheating).

Not knowing much about RX-7’s and the rotary engine I thought I would register hear and see if any of you experts have any thoughts.

PS, the only other thing I noticed that I am questioning is there was oil at the clamp for the tube right after the turbo and a little oil spray at a smaller 1” tube that is under that pipe. Is that normal? I know on my old SVT Lightning the PCV would let oil through and result in oil in the intercooler. Is this something similar?

Thanks for any help.

 

PPS, when the car was started for the first time that day there was a fair amount of white (not blue or brown/black) that was coming out of the tail pipes. It did not smell like coolant. Not sweet at all. It smelt more like gas and it went away after the car was idling for a couple of minutes. The car had also passed emissions test with flying colors.

 

I would venture to guess that the car has a bad cap on the AST. I imagine the dealer filled the overflow tank up to 'full', and had the AST and radiator fill points full as well. The car naturally had coolant expand into the overflow and then...overflow as it sat there. This is definitely where the coolant came from, the overflow tank is right behind the passenger headlight.
Now keep in mind that a leaking coolant 'O' ring will also let the coolant system overpressurize due to combustion pressure and force coolant out thru the overflow. But that car has way too low of miles to be suffering from that, unless it was overheated at some point in its (short) life.
Have them put a new .9 bar cap on the AST. Fill the coolant up at the thermostat/water pump fill point. Make sure the AST is full with the engine cold. Make sure the overflow tank is no more than 'full' on the dipstick. Now go do your test drive again and then let the car sit again.

 

Thank you very much for your input. I don't know what the AST is but I will do a search on here and look it up. I have some pics that I just looked at and I see a spot where the coolant "may" have been leaking from but it could very well be tha the coolant just puddled there. I will post them up.

 

The Air Separater Tank (AST) is a spring loaded radiator type cap sitting next to the intercooler.
Baja is probably right, but just FYI, the stock temp gauge is NOT linear. If the needle moves off of roughly an 8:00 o'clock position, the car likely has already over-heated. If you buy the car, get an aftermarket temp guage ASAP. A little oil is not uncommon in the intake track, but it shouldn't be excessive...pooling, dripping from the couplings etc. That could be an indication of other things.
If you haven't already, and before you go back the dealership, read through the other links under BUYING here:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/

 

Here are the pictures I took in the general area where I thought it was leaking. As mentioned above this may just be where some coolant collected.






Is that black seal right under that metal elbow known to leak?

 

Thank you.

 

Here is one spot where I saw a little bit of oil. The other I didnt take a picture of but it was about a 3" Hose in the same general area (that I think was right after the turbo) that was verticle and there was a little oil where the rubber hose met the metal tube held by a band clamp.

 

And my last stupid question. Is a fair amount of white moke at start up that smells like gas (not sweet like coolant) ok? It lasted for a couple of minutes then went away. No smoke while driving either.

 

I would recommend hooking up a temporary boost gage for the next drive (10/8/10 pattern), and don't buy without having a compression test done. They are both cheap insurance!

 

TTT regarding pictures, and smoke question. SOme say a white smoke that smells like gas on start up is ok, others say it is coolant and not ok but why does it smell like gas if it is coolant?

Thanks.

 

Well the dealership called and they said they didn't even need to put the car on the hoist to find the problem.

They told me when they checked the coolant level it was overfilled and what must have happend is when they changed the coolant when they got the car they must have put in too much coolant. This makes sense but I have no way to verify if it is true or not. I asked them that once they changed the coolant again to run the car, drive it and then let it sit for a while and see if it leaks again.

We shall see. Would be nice if this is in fact what the problem was.

 

^Agreed. If they are a MAZDA dealership, it should be pretty easy to get a compression test done....though they might have to put it up on the lift for that.

 

Yesterday morning temperature in Dallas was about 50*F...the 7 barely smoked for less than a minutes (last start was last Saturday). Every car is different so if this 7 smoked heavily & longer than few minutes I would look closer.

Do a simple bubble test...

Couple months ago I dealt with a coolant leak at the overflow tank...turn out the used Pettit alum ast has a bad seal at the neck due to corrosion.

In the pictures you can see the overflow tank is overfilled.

 

Some info:
It was about 45 when I test drove the car and it was the first time it was started in over a day according to the dealer. It smoked for about 1 minute 2 max. The smoke dissapeard within a couple of feet of the tail pipes and it smelt like gas not a sweet coolant smell.

 

Ditto

 

my car did the same thing for about a month and than just stopped. same with my friends car, his was a coolant leak real small, but ran good and strong. mine was because i boosted when it was cold like an idiot when i was young and stupid.
mine no longer smokes now, but my guess is that is was overheated or boosted, i would take compression tests though for sure, like said above, it is really cheap insurance.

 

so whats the verdict?

 

Well they drained some coolant and said they tested it by driving it and letting it sit for a while and everything looked good. I told them I would hate to drive all the way there again and test it just to find out that wasnt the problem. They reassured me that it was the problem so gave them a deposit and I am going back this Friday to test it again. If all is good I will drive away in it.

 

hey, just a quick question, from my past experiance with living up north in the cold. when its cold out side and you exhale....it smokes, could it be that its cold enough that the exhaust is causing "steam" due to the temp? just a theor, maybe try starting it inside the mech bay area where it is warmer and see if it still smokes, that might be why it doesnt smell like coolant and does smell like gas. my .02 good luck.

 

Yup it could very well be condensation and smelt like gas since cars will run a bit rich when cold. Also the cats are not warm yet so they do not burn the excess fuel. It is a possibility thats what it was for sure.

 

^ NTIMD8, I hate to be the barer of potental bad news, but please hava a look at this thread regarding the car in the canadian section of rx7club.com

https://www.rx7club.com/showthread.p...6&page=1&pp=15