jhammerrx7

iTrader: (5)

Thanks for checking. What your saying is exactly right.
Its holding pressure overnight and won't suck back any from the overfill.

DaveW

Already said, but, IMO, you have a blockage somewhere in the overflow system (cap, tubing, nipple on O-F tank, etc.). Do you have the proper spring-loaded cap on the system?

jhammerrx7

iTrader: (5)

I had a 13 psi cap on the system and I found it to be faulty. Air was escaping out the top of the cap when the spring would collapse.
I need to order an OEM cap, but would you stay with a 13 psi cap or a 16 psi?

Also, I tried the pressure tester again last night and instantly I heard a hissing sound.
I sprayed all my coolant lines with soapy water and couldn't find a leak.
Turns out the pressure tester that I rented was faulty. It was leaking on top of the universal part that attaches to the top of the filler neck. So, I didn't get a good chance to pressure test it again after installing a new OEM t-stat.

I can't locate another one in town to rent.
I may just purchase one.

Scrub

iTrader: (25)

What type of radiator hoses do you have, and what kind of clamps are you using to hold them on?

When you were burping the system of air, did you have the heater on full and the vents set to defrost?

jhammerrx7

iTrader: (5)

Not sure of the manufacturer of the radiator hoses.
Picked them up at Napa a couple of years ago when I did my front mount.
Hoses look good and I can't find any leaks.
I am using the normal screw type hose clamps, with a back-up spring style hose clamp below them.

When I burped the system I had the heater on full blast but now on defrost.
I had it on vent (blowing towards the driver). Does this make a difference?
If so I will definatly try it on defrost.


I appreciate all the help guys. I feel absolutely stupid not being able to figure this out.
Talk about frustrating.
It may end up being something simple that I completely overlooked, but I think I am going about it the right way.

I am going to check the nipple on the overfill tank tonight.
I can blow into the tank and also suck back, so I don't believe its a clogged or blocked overfill hose, but I will double check.

RCCAZ 1

iTrader: (10)

I chased a coolant problem similar to yours (although mine ran cool as a cucumber) for nearly 6 months. Tested, pressurized everything to take readings (mine would hold pressure), but the car was still pushing coolant into the overflow and not siphoning back in. Ended up that I had a bad 13 psi pressure cap.

I thought I had tested it more than once, but when I tested it a week or so ago, it would "crack" at 13 psi on the tester, but fall off to about 8 psi within a minute or two. Take it from me, just because you "bought" a new cap, don't assume that it's good. I take my pressure tester to the store now and test each cap to ensure that I have a good one before purchase. I've had to test 3 or 4 "new" caps in the past before I could find one that performs well. Make sure the cap is good and that the "seal" on your AST is snug.

The other "gurgle" symptom you've been describing in several of your responses when you release your "fill" cap was happening to mine as well when my pressure cap was not sealing properly. Check the cap again. It should move up to 13 psi before cracking and hold pressure. If it doesn't, that's your likely culprit!

Scrub

iTrader: (25)

The reason I was asking about the clamps was this. A forum member was having an issue where his coolant system would stay pressurized even though the car was off and cool. Coolant would gush out of the filler cap after sitting overnight. We found the problem to be one of the clamps on the radiator hoses was too loose. Coolant would very slowly seep out of the hose when warm but then when shut off would suck air back into the system. This guy has a short fuse to begin with so he was a little upset at the situation hahaha.

It sounds like you have redundancy on your radiator hoses so I doubt that's the problem, but check when the car is hot to see if the little reinforcement threads are wet on the coolant hoses.

jhammerrx7

iTrader: (5)

Will do. Thanks for the heads up.

On another note, does anybody know where to find good heavy duty caps for blocking off coolant nipples like on the bottom of the radiator?
I'm tired of the piece of hose with a bolt in it. I would like to clean them up but all I can find around town are vacuum caps and one already failed on the thermostat housing.

jhammerrx7

iTrader: (5)

I went and rented another pressure tester from another store last night, this one actually worked.

I pressurized the system to about 19 psi and left it overnight.
Over a 13 hour period it dropped to about 17-18 psi.
No visible leaks, nothing on the floor.
I haven't pulled the lower spark plugs yet and hand turn the engine to see if any coolant spits out.

Is 1 ot 2 psi drop over 13 hours possibly normal with a pressure tester?

Also, is it possible if I have a small pin-hole leak in my coolant o-ring that 19 psi on the coolant side may not be able to push coolant into the engine, but say 100-120 psi of compression on the enginer side to push exhaust into the coolant?

DaveW

Yes, it is possible that a coolant o-ring can leak either way exclusively, or both ways, depending on its and the o-ring lands' exact conditions.

Dave

jhammerrx7

iTrader: (5)

Thanks Dave.

Do I dare push the pressure up on the coolant system to the high 20's for psi and see if there is a change?

Also, I picked up some new overfill hose last night and I am going to replace the existing just in case there's a leak that I can't find.

I also need to order an OEM rad cap. Would you use a 13 psi or 16 psi?
I have the FC filler neck/AST deletion done on the car.

Thanks again for all the help guys, Josh

DaveW

Dave

jhammerrx7

iTrader: (5)

Thanks again, got a .9 bar cap coming from Malloy.

RCCAZ 1

iTrader: (10)

Again, just test it to make sure it cracks and holds pressure properly before installing. Looks like your taking the right steps. I agree with Dave, do NOT overpressurize. The max that Mazda specifies in the shop manual is 19 psi, but I think that was based on the early assumptions that a 16 psi cap was being used. With that being said, I think applying 16 psi is plenty if running a 13 psi cap, but again, that's just my opinion.

You might also want to check your fill neck where the cap connects. I've seen some where the cap attachment grooves get worn over time and could possibly cause the cap to not pull down and seal properly.

Good luck!

jhammerrx7

iTrader: (5)

Thanks for the heads up. Unfortunately the pressure kit that I have has a cap tester, but my cap will not fit on it, so at this time I don't have a way of testing the cap. I might call around some shops tomorrow to see if anybody has a kit and if I could test my cap real quick.

At lunch I checked my car and the pressure was a little lower than 17 psi, but it has been under pressure for about 15 hours.

I'm gonna change my overfill tube tonight and see how it goes.

My FC .9 bar cap should be here on Friday or so.

I also did check the FC filler neck where it attaches to the thermostat housing.
While it was under pressure I sprayed soapy water all around it and there wasn't any bubbles.
Seems like its holding pressure pretty good. Probably wouldn't hurt to change the o-ring below it though.

gracer7-rx7

iTrader: (16)

FWIW, I think the FSM specifies pressure of 14 PSI when testing

jhammerrx7

iTrader: (5)

Another update guys.

I received an OEM .9 bar cap from Malloy on Thursday.
Topped off the fluid, made sure the overfill wasn't above full and drove around for most of the day.

Temps held up great, but everytime I would shut down the car I would check the overfill level. The level kept rising and rising throughout the day.
There were a couple of periods where I didn't drive the car for a couple of hours.
One would think that within a couple of hours the engine should have sucked back any coolant that was pushed into the overfill when the coolant expanded, but it seems as if it is being pushed out and not siphoned back.

Per my previous post the system held 19 psi well overnight and I just replaced the overfill hose so I can't see how air could be entering the system during cool down.

By the end of the day I had the coolant buzzer come on once but temps never went above 93C during "spirited" drives. When I parked the car that evening the coolant level in the overfill was just under the highest mark.

If the car is not overheating why would the pressure keep reaching more that .9 bar to open the radiator cap and force coolant into the overfill? Is it just normal?
If so, wouldn't driving for an hour straight eventually push all your coolant into the overfill? At what point would the radiator cap stop opening?
I guess I am just confused on why it keeps building enough pressure to open the rad cap.

Could it be possible that my water pump is cavitating and creating air in the system? Would it be worth the time to replace the pump at this point and see what happens? My only next guess is that it must be an o-ring allowing exhaust to enter the coolant. It may not be superheating the coolant causing the engine to overhat, but simply displacing coolant into the overfill. At some point I would be low on coolant in the engine and it would eventually overheat.

What do you think guys? I am out of ideas.

RCCAZ 1

iTrader: (10)

What you describe above is normal. As the car warms up and coolant expands it WILL slowly raise the level in the overflow tank (hence the name). If your system is pressurizing eventually the overflow WILL overflow. Checking the overflow stick when it's HOT is meaningless since the car is still warm and if sealed properly, will siphon coolant back into the engine as the engine cools down. I usually wait until the next morning when the car is totally cooled down to get my answer.

Again, if you checked the car HOT, this will be normal. You need to wait until it's totally cooled down and check the level then. Are you still running an AST, or did you do the elimination kit? I've run mine both ways, and prefer the AST since it gives the system a better way (IMO) of purging any air from the system. Again, JMO!

Again, I think you are confusing "pressure" with "expansion" which happens normally when coolant starts warming up. I'm still voting on a small air leak somewhere or a cap that's not sealing properly. You really need to get an adapter for that pressure tester so you can test the cap.

Yes, it's a possibility, but I'd test the cap first. It's an easier thing to do than changing the pump.

This is still a possibility, but the fact that the car is not overheating works in your favor. A "very" small o-ring leak could still be the culprit. Have you been "bailing" coolant out of your overflow to keep the level at or near the "F" mark inbetween tests? I found in the past that if my overflow tank was "overfilled" above "F" the system had a harder time siphoning coolant back into the engine. Just a thought.

Try some of these things. I know it's a PITA, but since you're not overheating you still have time to find the solution. You do have a yellow "Lisle" funnel, don't you? If not, you should go online and purchase one. They are around $40 and attach to your fill neck. That way you can see if you're getting steady bubbles generated from your system when running.

Keep us posted.

jhammerrx7

iTrader: (5)

Thanks so much for your help.

jhammerrx7

iTrader: (5)

Hey guys, a quick question.

Found this on another thread, but there was no answer to the question.

"I was wondering for people with the FC filler neck how the overflow can pull the coolant back into the engine, since the cap requires positive pressure to open, how can negative pressure open the cap to pull it back in?!?"

I am also curious about this.

Any help?

DaveW

The cap has a low pressure check valve that opens to let the coolant flow in reverse as the engine cools down and a slight vacuum develops in the engine

jhammerrx7

iTrader: (5)

Thanks for clearing that up.
I always wondered how it actually worked.

jhammerrx7

iTrader: (5)

Over the weekend I flushed the coolant again and started to refill/burp.
Since the refill I haven't been able to get any kind of warm or hot air from my defrost. Still seems air locked.

I took a couple of quick vids.

The first vid is at 40 deg C on start-up.
The little chirp is my alarm from the battery being a little low.
The vid goes until about 51 C over a couple of minutes.
I noticed that I was getting some pretty good smoke from the exhaust.
It has never smoked like that before. I just checked the coolant system last week and it helo 19 psi for quite a long time, and the smoke didn't really smell like coolant.
It smelled more like fuel, it made my eyes sting pretty quick.
From the amount of coolant that has been spilled over the last couple of days my belts are squeaky and I think the idler pully for the AC and power steering pulleys is getting a little bad. You can hear it click once in a while like a bearing is going out.
I shot a vid of the Pineapple Idler pulley also. Great product.

http://www.youtube.com/watch?v=P7U0B1x4bgM


Next little clip is of the exhaust smoke.

http://www.youtube.com/watch?v=LnMrfRPm-Z0


Vid pics back up about 1 min later when the temp is at 81 deg C.
The coolant is starting to mix a little and looks quite darker than it is.
I just flushed and refilled with 60/40 water to Prestone coolant.
Fluid level raised in my funnel like it should.
The bubbles starter around 65-70 deg C.
Smoking stopped except for one little puff.
Temp kept rising without any warm air from my defrost or vents.
It started boiling out of the funnel so I shut her down.


http://www.youtube.com/watch?v=Rjn8woqnDDo


What do you guys think? It may still need to be completely burped but I don't know why its being such a PITA. I should definitely have warm air from my defrost if the temp gets that high.

RCCAZ 1

iTrader: (10)

Really weird. It's acting like the thermostat is not opening. Also, the change in coolant color and amount of bubbling has me very concerned. If it were just air trapped, you'd see some bubbles followed by periods of relative calm, but yours is really cranking out bubbles. I've had pretty big air bubbles in mine, and once they surface, the coolant level in your funnel will drop very fast, but yours just keeps filling and expanding. Did you by chance feel your lower radiator hose to see if it was cold or hot? Do you have your Power FC adjusted so that the fans come on at a lower temp?

jhammerrx7

iTrader: (5)

The lower rad hose is indeed hot, not as hot as the upper hose, but hot.
I believe it is circulating, but I have not idea why such large bubbles at higher temps and no bubbles at start-up or on a cold start.

I have the PFC turning the first stage of fans on at 86C.
I don't have the AC working, but if needed I can push the AC button to get the second stage of fans to kick in.

Also, if it was an o-ring failure should I see bubbles at lower temps and on cold starts?
Or would the bubbles be trapped and accumulating behind the t-stat? Would air trapped behind the t-stat still get it hot enough to open, or does it need the water to transfer the heat to the t-stat?
Wouldn't the jiggle pin help with letting the bubbles pass through without the t-stat opening?