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-   -   SEARCHED: positive coolant pressure when car is dead cold-what's wrong? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/searched-positive-coolant-pressure-when-car-dead-cold-whats-wrong-188207/)

KevinK2 06-03-03 01:51 PM

disconnect hose at top of ast, that goes to overflow tank. make sure you can blow thru it (bubbles in exp tank), and also suck coolant back up. this and new ast cap should do it ...

CCarlisi 06-05-03 10:33 AM

UPDATE:

I replaced the AST cap with a 13PSI cap from autozone. I removed the upper hose and blew through it. I heard airbubbles in the overflow tank. I was also able to draw coolant back up through the hose. Yes Zoomzoom coolant does taste sweet (I can't believe the crap I do for this car).

The result.........NO DIFFERENCE!

Any other ideas? :p

I'm going to try to get a smog sniffer test done this week and I may also do the ast removal for the hell of it.

CCarlisi 06-05-03 11:19 AM

^

spurvo 06-05-03 04:57 PM

Too bizarre. I was betting on cap not relieving pressure.

Coolant tases wonderful, especially when spraying into the mouth when blowing on the filler cap land to perform the poor man's system pressure tester. Turns out I could only put a few pounds that way, and the splash back was not so fun. NO COMMENTS about what porn stars must feel like.... :)

So I tried sealing it all up, folding the upper rad hose, then BITING IT. I successfully provided cap opening pressure. And now I've disgraced myself!

I bought a system tester from Napa. The biting thing was all well and good, but I couldn't really quantify leakdown, nor search for coolant trails. Less than optimal.

There, I just wasted this response. I are an post whore.

If you are loosing coolant while you drive, you most likely have blown O-ring syndrome. It's probably holding the 13 psi in the system because the O-ring failure is very slight right now, only happens with engine running. On shut off, the ring is sealing up again, so pressure does not bleed back into the system, nor out the cap, except for the heat soak expansion. If there are no tiny bubbles, then the last resort is to measure for HC's at the filler neck when fully warmed up while running at 2000 rpm or so.

So say I. But then, I blow filler necks.

vudoodoodoo 06-05-03 05:35 PM

Hmmm...
Coolant goes to the overflow tank when you shut off the car and the engine cools down right?
Maybe the hose the goes from the AST to the overflow tank is kinked or something that could prevent the coolant from going to the overflow tank.
So there is coolant that is trying to go to the overflow tank that has no where to go. It would get backed up into the AST to the filler neck.
Idunno, I'm just taking a wild guess here. :D

spooledUP7 06-06-03 09:51 AM


Originally posted by CCarlisi
UPDATE:

I replaced the AST cap with a 13PSI cap from autozone. I removed the upper hose and blew through it. I heard airbubbles in the overflow tank. I was also able to draw coolant back up through the hose. Yes Zoomzoom coolant does taste sweet (I can't believe the crap I do for this car).

The result.........NO DIFFERENCE!

Any other ideas? :p

I'm going to try to get a smog sniffer test done this week and I may also do the ast removal for the hell of it.

You were able to suck, but could you blow and make bubbles into the overflow tank?

CCarlisi 06-06-03 10:29 AM

lol I feel like I'm being setup for a joke. The answer is "yes."

I think it's safe to assume the motor is shot. Last night I drove it for about 20 minutes, shut it off, let it cool for 30 minutes and then wasn't able to restart it. I cranked it over for several minutes. When I was cranking it my friend said he smelled coolant coming from the tail pipe. I let it sit for several hours and then tried again. It started but was only running on one rotor. After a few seconds the other rotor putted to life and let out a huge cloud of white smoke. After that everything went back to normal. I drove it home and parked it. I've been getting low coolant warnings more frequently over the past week and similar, though less significant, starting problems. I can also now hear water running through the heatercore.

I'm not going to have enough personal time to R&R the motor until august and can't find anybody locally who will do it at a reasonable price. Therefore the car is going to rot in my garage for the foreseeable future :(

I want to thank everybody for all the help touble shooting this problem. I'm sorry the story didn't have a happy ending.

Best,

Chris C.
94 DOD 71,000

vosko 06-06-03 10:54 AM

cough
rad caps
cough

:)

vudoodoodoo 06-06-03 01:10 PM


Originally posted by CCarlisi

I'm not going to have enough personal time to R&R the motor until august and can't find anybody locally who will do it at a reasonable price. Therefore the car is going to rot in my garage for the foreseeable future :(

Sorry to hear that man.

I'll do it!!!
It would be slow though cuz I am only free on weekends. :D

Have you tried BPR? They're in Salem.


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