wstrohm

Silly question, but have you inadvertently switched the two radiator caps (don't ask me why I thought of this)?

---- Bill

bdennis

No, the caps aren't switched. Anybody else have an answer?

Fritz Flynn

iTrader: (263)

If bubbles are rising up in the filler kneck at operating temps (above 180 or whenever your thermostat opens) then you probably have a bad engine.

If you keep adding coolant to your car it will overflow from the reservoir because you're adding too much coolant. The buzzer is probably coming on because you have air in the system. Disconnect the hose on the back side of the manifold and take the filler neck top off, squeeze the lower radiator hose a few times but not so aggressively that you spew coolant from the kneck or the upper manifold, and let it sit over night. Check the level in the overflow bottle the next morning and if it's good don't add any coolant. Put the hose and the top back on and wait for the buzzer to come on. Hopefully it won't. If it does don't panic. If it stays on for longer than 1 minute or the temps go over 210 then shut the car off and check the reservoir again. If the reservoir is still at the same level then it's obviously not feeding the engine due to bad pressure or a pinched hose.

bdennis

By bad pressure do you mean a bad coolant seal or a bad cap?

Fritz Flynn

iTrader: (263)

Meaning the caps are not sealed or a hose is leaking.

If you bring your car up to operating temps meaning the thermo is open and you have a constant stream of bubbles rising to the top then combustion is not sealed off and you will eventually need an engine. Just drive it becomes unreliable IOW you have trouble starting it. May last a while in this condition if you're not driving the car hard.

4CN Air

iTrader: (7)

well I believe the block seal has worked, I still have to get he coolant system completely purged and see if after a couple heat cycles the fluid level stays steady.

BTW: I believe the "CRC Block Weld" has been updated to "K&W (one of CRC's brands) Permanent Metallic Block Seal". I was able to purchase it and the purple cleaner at Advanced.

I'll keep everyone updated

4CN Air

iTrader: (7)

FOLLOW UP:

Loosing coolant again, but more slowly. I think another dose of block weld would fix this (I only used 2 cans), but I got a good deal on a new engine, so no more patch work.

The leaky engine will become my first attempt at a rebuild. Wish me luck.

t-von

iTrader: (8)

I've been experiencing the same issues. I guess it's time for me to try this process also. If it doesn't work, then that's more of an excusse for me to go ahead and install the 20b.

WhiteR1

Why didnt i find thid thread till now? Lame looks like i to am in the same boat.

93red

i had the exact same problem.. the car would drive fine.. and then if i came to a stoplight, and continued to give it gas, i could hear the gases pushing the coolant out of the overflow tank.... my car has been in the shop for 30 days now.. i expect the rebuild to be done next week... and sad thing is i just bought the car 2 months ago..

t-von

iTrader: (8)

Well I know one thing, once I finally break this engine down, I'm going to half bridge the engine, install 9.7 compression rotors and a Gt-35r turbo and put that bad boy in my 1st gen. That would be a nice street able set-up.

Dcrasta

Waaa same problem for me

CantGoStraight

Just a heads up but when you pull that motor out you'll need to tear it down right away or it will rust beyond use in the internals where the coolant leaked into the combustion chamber. It won't leave you much to rebuild once that happens.

4CN Air

iTrader: (7)

thanks for the advice, it'll be useful for the many that are watching this thread. I ended up buying a slightly used ported engine and selling mine to a rebuilder. The simple engine swap turned into a single turbo conversion and all out attack on my engine bay, haha. It's all been for the better.

POS7

Any of you guys ever have any overheating problems prior to the coolant seal giving way (confirmed via aftermarket temp guage)?

tsmysak1

I had the same symptoms, almost to a tee.

It is still running, mainly because I don't have the other engine built yet. The block weld sort of worked, but I just accepted it as temporary at best.

One thing I noticed is this. The compression cycle will put small debris into the coolant. This compromises the seal on the radiator cap that goes to the overflow. Once this return seal is not sealed anymore, then the temperature is likely to go up or you will see more and more coolant pushed out into the overflow. You can clean the cap and get some drivability out of it, if the o-ring seal is not too bad. It just progressively gets worse though, so plan accordingly.

4CN Air

iTrader: (7)

No overheating here.

Silverstone

Check out my parallel running thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/oh-boy-could-i-possibly-have-coolant-seal-failure-544249/

I'm currently checking out a new product called SteelSeal. Supposed to be better than regular Block Weld. Does not contain suspended particles that are more likely to clog but we'll see. The tech there sent me out some as freebie to get rotary dudes to check it out. I'll let you know if it works.

F0RSAKEN

FYI, the PO of my car used that stuff, and now my heater doesnt work.

Silverstone

According to the tech guy I talked to at steel seal, the antedote to any clog with their product is white vinegar. If you try it, let me know because I haven't used it yet.

t-von

iTrader: (8)

Update! Well I guess I got lucky. It wasn't coolant seals for me. My 104K original miles engine didn't have any white smoke problems ever during start-up, just coolant boiling out the overflow tank when the car was shut off.

I was prepared to do the block weld. I was flushing out the coolant system. I have a weird way of bleeding the air out the Fd without running the engine but it works. Usually I will fill the system with the TB coolant line disconnected. Then I will top up the system. When I think it's full, that's when I will place my mouth over the filler neck and blow. This will force any air out the upper coolant TB line. I then keep repeating (filling and blowing) till nothing but coolant comes out.

That's my normal bleeding method however, this time when I reconnected the TB coolant line and blew air into the filler neck again, I could hear air bubbles in the overflow tank. That's never happened before. I then pinched the line leaving the AST to the coolant tank and did another blow test and this time I could feel the system pressure up in my mouth. That's when I realized that my AST pressure radiator cap may be faulty. As a test, I replaced the cap with another one off another car. I did the blow test again without pinching the line, and this time no air bubbles in the coolant tank. Went for a test drive and now the coolant no longer bubbles out the coolant tank.

Even though my old cap look to be in good shape, apparently the lower seal below the spring wasn't seating against the lower part with-in the AST filler housing allowing for the pressurized coolant to back flow out the AST and back to the coolant tank. The blow test with my mouth proved this because obviously I don't have enough mouth pressure to blow fluids past a good working cap.

LOL all this time it was the damn radiator cap.

tphan

^^^^
same here...bad ast cap after replacing stock ast. It is fixed now.

bigbadbenny3

I am having similar symptoms to everyone here. Just want to clarify.......if it is in fact a blown o-ring I should be looking for a cloud (white I'm assuming) at startup that smells of coolant?? Or are there other signs that will verify a blown o-ring? Thanks for all the great posts on this topic, hopefully I will have my car diagnosed this weekend.