i suspected having a bad coolant seal, and when we pressure tested the coolant, it held about 13.5psi for 10-15 minutes before we decided the seals were good...

should we have left the pressure test go for longer than 15 minutes?

 

I've had mixed results with pressure testing. Best signs of a bad coolant seal are bubbles in the coolant, rough running on a cold start, and smoking, not to mention coolant loss. Also, if the overflow tank continually fills with coolant, that's another sign.

Dale

 

you tested ok..if you would have had a leak in your cooling sytem it shows up on the gauge..it sort of decreases in the reading ..not like a compression tester where the reading is held by the schrader valve on the side of the tester

 

but what i'm thinking is the cracked oring may have sealed up since the engine was hot when we did the test... i have all the symptoms of a bad coolant seal, but the pressure test checks out ok???

unfortunately i think i'm with dale on this one.

 

Yes,agree with Daleclark..sure sign is when you start the engine with the rad cap off and it "fountains " coolant ..(spews big time)..sometimes if you hav just changed the coolant or if you have added coolant you can encounter an "air lock"..where there is a bubble of air trapped along the path of the system..(like the heater core).. or thermostat gets stuck and the hot coolant expands and pushes the coolant out(change thermostatinthat case)..air lock is fixed by allowing the system to heat up with the cap off,squeezing the hoses to expel air (getting the coolant to force the air out to the open cap)fwhile you have the heater gin full tilt.then top the sytem off and drive ,cool down check,top off the system and the bottle..bit of info for ya..edit..sorry about error in typing!

 

I got bad coolant seals, I can hear coolant shoot out into the reservoir when I rev up to 3000 rpms. Also smokes when I start it up and idles rough.

 

hmmm, i'm going to go out and start it cold in the warm garage and see if it smokes...

 

Here's what I use to check for bad coolant seals/head gaskets. It goes between the upper radiator hose and radiator. Just thought I would share.




chuck

 

i think if i had 550 dollars, chuck, i'd probably be buying a rebuild kit and new seals........ what do you think

 

Here's something to try. Pinch off the heatercore line, then pressure test the cooling system with the pressure tester again. This time go to a high pressure. I go somewhere around 17psi with plastic endtank radiators and 20psi with radiators with metal end tanks. 13.5 psi is just the radiator cap pressure release limit. Yours/a good cooling system can/should take lots more. Do this with a cold motor and leave it for 20 minutes or so. Remove the leading plugs and rotate your motor every few minutes and try to see if coolant is in your motor. You may have to use a mirror. Only problem with this is the limit of pressure your forcing on the cooling system is small compared to what the combustion chamber is putting on your seals.

If thats does not work then try this. pressureize the cooling system to 10psi and start the motor. See if the pressure drops or goes up with the motor running. Let it idle for around 1-2 minutes then raise the idle to 3000rpms and watch the pressure gauge. It "may" go up slowly because the heat of the coolant. It if jumps up then your coolant seals are bad.

I like pinching off the heater core just incase its weak. Hare to replace. everything else is easy and if it does not hold to 20psi its weak in my book and needed to be replaced anyway.

chuck

 

NAPA sells a Coolant Exhaust Gas Tester for around $50. It is a glass tube that you partially fill with a blue liquid that is supplied. If there are exhaust gases present in your coolant system the liquid turns green. It is a much more conclusive test then pressure testing. What we have found is that pressure testing works very well to determine if there are any other weak spots (radiator, hoses, waterpump, etc) that may be allowing air into the system but the exhaust gas test tells us immediately if the coolant seals or something else internal is allowing combustion gasses into the coolant system.

 

My car will have some white smoke sometimes on cold mornings, but it goes away after about 2 min. I will sometimes have a rough idle on cold days for a few min until I get up to normal operating temp. Is this a sure sign of a bad coolant seal? I was told the white smoke was oil that was still sitting at the bottom of the rotor housing and had not been burned off yet. Is this true, or a possibility?

thanks for the info,
-josh

 

Yes, the hydrocarbon test is the #1 test to use if the pressure test isn't conclusive. Most garages (even places like Goodyear) can do the hydrocarbon test for about $30 if you don't want to buy a tester.

 

[QUOTE=recon fd]

1. My car will have some white smoke sometimes on cold mornings, but it goes away after about 2 min.

2. I will sometimes have a rough idle on cold days for a few min until I get up to normal operating temp.

3. I was told the white smoke was oil that was still sitting at the bottom of the rotor housing and had not been burned off yet. Is this true, or a possibility?/QUOTE]
--------------------------------------------------------------

1. This is normal. Combustion produces water vapor which condenses in the exh while it's still cold.

2. This is not normal, COULD be a sign of bad coolant seal, but MANY other things can cause that.

3. See # 1

The signs of a coolant seal failure (not all will necessarily apply to every case) are:
a) continual generation of air bubbles in engine
b) loss of coolant w/ no external leaks
c) excess coolant in O-F tank, low coolant in engine (could be due to other causes like bad AST cap, hole in coolant return line from O-F tank)
d) one rotor may not run for a while after starting due to coolant on spark plugs
e) "champagne" bubbles in filler neck on running

The best way to diagnose a loss of coolant is a pressure test, but even that is not foolproof. If that is not conclusive, the hydrocarbon test (as mentioned above) is more conclusive w/ regard to coolant seal failure.

 

Thanks for the help. I am going to do the hydrocarbon test.

-josh

 

We have actually worked on cars that passed the pressure test, then failed the exhaust gas test. When we broke down the engine, we found that the coolant seal retaining wall was eroded away completely in sections.

 

interesting. thanks for the info.

 

I thought my rough idle feeling could have been coused by engine mounts going bad. Is this the same feeling, or would this feel completly different.

thanks,
-josh

 

I've been chasing down a coolant leak myself that was lettign air into the system and forcing all the coolant into the reservior tank. I think I found the culprit, the small 3" right angle bent hose underneath the TB.

hope that's the case. I may go buy this exhaust gas tester also.

 

buy one and post the results!

 

Just to make it a little easier for people to source the tester these are the NAPA part #'s that are on our kit.

Universal Block Tester BK 700-1006
Block Tester Test Fluid BK 700-1366

They sell them together as a kit under a different #, but if they can find either of these in the catalog then the kit will be on the same page