I have been having all kinds of coolant problems lately but the car is running great, idling perfectly, and I have about 18 to 20 in of vacuum at idle. When I shut the car off as the pressure builds up I am hearing a hissing and I have even seen some spewing liquid and air coming from under the alternator. I checked under there and the only hose I could find I had replaced last week. It is fine. That is more behind the alternator than under it anyway. Could this be a problem with the seal of the water pump or the pump itself? Also the car appears to be leaking coolant from the seal of the oil pan but it may be somehow dripping from elsewhere and running along that seam. There is no oil dripping there, just coolant.

So I guess the real question is...what are the symptoms of a failed coolant seal? How do I tell if there is coolant in my oil? If I had a seal blown this badly, wouldn't I be having starting or idling problems and a huge cloud of white smoke every time I started her up? I guess I will have the coolant system pressure tested and see what they tell me. I assume they will be able to tell me if it's a coolant seal or just a minor leak or two. Hope she's not down for good.

 

if your coolant seals are bad then you'll get clouds of sweet smelling smoke coming out from your exhaust. If not then its more likey a leak somewhere.

 

it will not smoke alot unless you have a big breach or you let the car sit for a week or two. when you start it will try to run on one rotor then clean itself off and burn up all the coolant in the engine making massive smoke..... my car did the same thing when i bought it

 

Check the weep hole on your waterpump housing. If the pump seals are bad, coolant leaks out through the hole.

Here's an interesting article on water pump failure. Note that they're talking about a different pump (I think the FD pump's weep hold is on the bottom, not the side like the example pump).

http://www.detroitdiesel.com/public/...bs/3-50-98.pdf

Another on why they have weep holes:

http://www.vtr.org/maintain/water-pump.html

 

Take your pressure tank off and look closely in that area there is a coolant hose that I think runs from the behind the coolant neck to the manifold. It sounds like a pin hole leak so most likely you will need to either remove the hose to inspect or pressurize the system. Anyway from what your describing I believe one of coolant hoses is leaking thats in and around the manifold.

 

Yes it can. Telltale sign is the coolant buzzer going off!

FWIW, my motor failed with a bad coolant o-ring.

You can say that the failure was accelerated by an incompetent tech that last worked on the car.

Lucky for me I had plans to replace anyway, otherwise I'd be seeking legal action against this shop!

Anyhow, enough with the bad news. I picked up my new FD Rx7 today from the Rx7 Store. New, as in with heavy mods.

https://www.rx7club.com/forum/showth...23#post1438123

 

SleepR1 is right, Mine has a bad seal. I don't get smoke at start up, although when they get worse they do. and I think most of the time they do.
Mine even passes a pressure test, But when I run the car the level in the overflow tank just gradually keeps rising till it overflows. when I shut it off and it cools down it will even pull all the coolant back into the system.
Napa sells a combustion leak block tester #700-1006 that you can use to test for combustion gases in the cooling system. I'm going to try it tomorrow. I already checked with a flue gas analyzer used for tuning boilers and it showed CO in the cooling system.
But if your leaking coolant below the Alt. its probably the water pump gasket or the water pump body gasket. The bolt that holds on the adjusting bracket for the Alt. is also one of the bolts for the water pump and body.
The water pump has a weep hole in the top and bottom.
Eric

 

Oh yes...this happened to me as well. Passed a leakdown test too, just like Eric's! Alas the 102,543-mile stock coolant seal was done.

 

Yes, just like SleepR1 and Air-Rex, my car has done the same thing. Runs fine, no smoke, just a gradual pressurization of the coolant system resulting in overflowing the...overflow. Eventually you lose enough coolant that you have to top it off.

I just did the sodium silicate/copper seal job. The one where you have to drain all the coolant and flush the system to get all the glycol out. So far, so good. Two days now and the coolant level has maintained itself....

 

Just a little clarification here:

A "leakdown test" generally refers to combustion chamber pressure.

A "pressure test" generally refers to coolant system integrity.

The ONLY way to do a "pressure test" is to have the engine stone cold and connect a radiator pressure tester. Generally speaking if you have a significant O ring failure the tester's needle will start dropping right away. This is not ALWAYS an indication that your O rings are shot or even on their way out. Keep on pumping up the tester multiple times over a 24 hour period. Look and listen for leaks or a hissing noise all over the engine with bright light and mechanic's stethescope. Even a small leak at a hose clamp can cause all kinds of problems. The two hoses that supply coolant to the turbos are notorious for leaking at the clamp.

If, when you start your car it fires up right away and does not blow any white smoke, you can be pretty sure your problem is NOT a blown O ring.

If you have still not found the leak UV dye is the next step.

 

Mine did'nt even show a problem with the combustion leak block tester I just tried. The fluid should turn green or yellow if combustion gases are present, mines still blue. huh
Eric