jermelle

Dropped my car off at a rotary shop and they informed me that my coolant seals may be bad. He stated that my car was sitting for about a week and their was still pressure in the radiator when he opened it.

Anyone have any ideas of what the problem is? Is this grounds for a rebuild?

just a little info on the car:
1994 mazda rx7
bone stock
68,000 original miles
car sat for about 8 months

Please help with any info!!

pugg57

well, i have to say first, why did they have it for a week and a half before they looked at it? i think you need a new shop are you burning coolant... white smoke out the exhaust all the time? continuously lowering coolant level? coolant in the oil? i think i would be want more than ONE possible sign before i plunked down that kinda change. maybe you have a cooling system issue not an engine-needs-a-rebuild issue?

jermelle

I just bought the car from San Diego. i wanted the car to get a thorough tune up or inspection before i drove it home. In my city there are no rotary shops.

Answering the question, I never drove the car a distance to see if it was burning coolant.
When i picked the car up from the arriving terminal. i drove approx. 6o miles and when i arrived at the shop, the car sounded like it was boiling or garguling.
Coolant did not have any bubbles or black spots when I initalliy opened the cap, before driving.

DaveW

It is possible to have some pressure in the cooling system if the ambient temperature went through large variations while sitting and they opened it while it was warm. As Pugg says, check other things first. The true test for o-ring (coolant seal) problems is the "champagne bubble" test. There are many threads on this problem. Do a search.

RX7Wishing

WRONG

The only TRUE test is to have a pressure test done of the cooling system. the bubble test is only accurate to a certain degree and can sometimes yeild false positives.

DaveW

I stand corrected. Thanks. What I meant to emphasize was that he needed to look more closely at the situation before having the engine replaced.

13Beast REW

They said that because of the pressure still being there, your coolant seals "may" be bad... their statement was true. The coolant seals "may" be bad. I'm dealing with a coolant seal failure issue right now. This is probably one of the few situations with a rotary engine where you may actually have a warning before the engine is severly damaged. If you cant get a pressure test as RX7Wishing suggested then you need to check the coolant level frequently in between drives to see if your coolant level is lowering. You can check the scent of the exhaust to see if there's a sweet smell to it (suggesting you are passing coolant through the motor) but if you made it through a 60 mile trip with out experiencing high engine temps or the coolant level buzzer then I doubt you'd be burning enough coolant for there to be a significant change in the smell of the exhaust. Like DaveW stated, you can also check the amount of bubbles that come up to the radiator cap. A few bubbles here and there is normal, but a more regular and heavy flow of bubbles is mostly likely a sign that combustion gasses from the motor are getting into the cooling system creating excess pressure. That extra pressure can create hot "air pockets", force coolant out of the cooling system into (and alot of times out of) the coolant overflow reservoir, and stimulate localized boiling.

Rotaries are hot enough under normal operation and dont like extra heat. If the temp needle ever moves above the middle you need to shut the motor off immediatley because if the motor is hotter than normal for longer than a short period of time you can expect the rotor and side housings are beinging to warp if they haven't already.

Bottom line, dont let the shop jump to conclusions. Try to test out the cooling system but it is possible that a rebuild may be necessary.

Don

RX7Wishing

i would of thought that if there was a loss of pressure then that would simulate a coolant seal failure. not if there was prolonged periods of pressure.. that dosent make sense to me. For them to say a coolant seal is bad because you still had pressure in the system. :-/

Experts.. Chim in here and school me.

also. Funk the shop's guess. Tell them you want a compression test and a pressure test.

13Beast REW

the excess pressure would be coming from exhaust gases from combustion seeping through cracks and/or gaps in a bad coolant seal

RX7Wishing

no shizzy.

after the engine is off there is no more combustion. so therefor no more pressure to be pushed into the coolant system. and since the coolant system now holds pressure you would think it would leak back into the combustion chamber, then making the coolant system lose pressure.

13Beast REW

yea, now that you mention it, a week does seem a little excessive

jermelle

the shop is suppose to give me a more detailed answer today.. 5/5 i will let you know what they come up with.

thanks for all the info.

jermelle

the shop is suppose to give me a more detailed answer today.. 5/5 i will let you know what they come up with.

thanks for all the info.

jermelle

the shop is suppose to give me a more detailed answer today.. 5/5 i will let you know what they come up with.

thanks for all the info.