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Took it on another drive today. Temps started spiking, but didn't seem as frequent, though it could be just me. Same thing as before, temp gauge spikes, AEM temp gauge will follow suit, then quickly settle back down. I'm guessing this is air.
When I let the car sit it's not as likely to have temp spikes, it seems to happen more often while driving it.
Car hardly took any water when I tried to add some today. we're talking maybe an ounce or two.
Took it on another drive today. Temps started spiking, but didn't seem as frequent, though it could be just me. Same thing as before, temp gauge spikes, AEM temp gauge will follow suit, then quickly settle back down. I'm guessing this is air.
When I let the car sit it's not as likely to have temp spikes, it seems to happen more often while driving it.
Car hardly took any water when I tried to add some today. we're talking maybe an ounce or two.
If it continues to spike after following Narfle's suggestion, exhaust gas has likely blown by main o-ring seals when running, resulting in those spikes, and continued loss of coolant. Make sure to not overfill the expansion tank. Also, air or exhaust could be drawn in after a hot shutdown, and full cool-down. The expanded hot coolant in the engine "shrinks" about 16 oz at ambient temps, and is under a small vacuum to draw it back from the expansion tank. Any tiny leak points will draw air in.
I think you can have the overflow tank sniffed to check for the presence of exhaust gas.
IAlso, air or exhaust could be drawn in after a hot shutdown, and full cool-down. The expanded hot coolant in the engine "shrinks" about 16 oz at ambient temps, and is under a small vacuum to draw it back from the expansion tank. Any tiny leak points will draw air in.
Yep. THAT is why I had suggested a pressure test a while back and posted the links from the FAQ
Originally Posted by gracer7-rx7
I also Suggest you go to the local auto parts store and rent a cooling system pressure tester aka radiator pressure tester and use it to check for leaks. That will also help you to diagnose if you have a bad coolant seal.
Yep. THAT is why I had suggested a pressure test a while back and posted the links from the FAQ
Great advice, I have 2-3 gauges, not very expensive and for DIYs, a necessity ! Those FAQ's have a lot of info on the cooling system .. I hope he reads them.
Great advice, I have 2-3 gauges, not very expensive and for DIYs, a necessity ! Those FAQ's have a lot of info on the cooling system .. I hope he reads them.
I've combed through them, I have to rent a pressure tester at this point, but my money is on the seal being blown and pushing exhaust gasses into the coolant system, hence the spikes. The car didn't take hardly any coolant today, though, and no smoking.
It only spiked while moving, but I took it for a drive and the upper radiator hose burst. My bet is exhaust gasses entering the combustion chamber like I mentioned. Renting a pressure tester after I replace the hose and fill the system is my next move. Prior to that it was popping the upper hose off the ast when I drove it, but now that it was clamped, that wasn't happening. I thought it might have just been air in the system, it's beginning to look otherwise.
Well, apparently zero places around here (or anywhere for that matter) have a correct upper radiator hose in stock. Which isn't surprising I guess. But now I'm forced to wait for the dealer to get one in stock, which means the car will be sitting for four days. Picture of the hose they said would fit, vs the actual hose. Also, where the hose ruptured is visible on the top right. Is it just me or does the parts catalog diagram not look the correct size of the hose I pulled off the car, either? looks to show only half of it, but the hose that came off the car is clearly one piece and much longer.
Last edited by SwappedNA; 08-31-19 at 01:41 PM.
Reason: Uploaded hose picture
If you don't have white smoke, my bet is still on a small pinhole leak or crack that's letting air into the system after it cools down. I was 100% convinced my own engine had blown coolant seals because I had very similar problems. I pressure tested my engine twice with two different styles of coolant system testers, and I was proven wrong both times.
If you don't have white smoke, my bet is still on a small pinhole leak or crack that's letting air into the system after it cools down. I was 100% convinced my own engine had blown coolant seals because I had very similar problems. I pressure tested my engine twice with two different styles of coolant system testers, and I was proven wrong both times.
Well, after the radiator hose finally gets here tomorrow, i'll fill the system up (again) and then pressure test it. That upper radiator hose exploded. I'm really hoping I am wrong on this one, but I'm starting to believe its the seals. I talked to Rotorsports, worst case scenario I'll have to come up with the money to have them work on it, if it is indeed the seals.
..... this whole time i'd been driving it with the caps the way they are, I don't know why whatever it was decided to show itself now, I'm going to try swapping out the caps for new ones. Anyone have any idea which ones to source at Advance? All they have is the 16 PSI....
I think this means you had the caps reversed until now, the one with a spring on the filler neck, and the one on the t-stat housing the plain cap with no spring, correct? That means you had no pressure in the system, and with just water, it would boil at 212F, and with 50% antifreeze, 224F. The pressure cap would seal the system, but there was no inner seat for the inner seal to contact. And the simple cap on the t-stat hsg would leave an open path to the overflow tank, for when the coolant got hot. You were likely doing a lot of local boiling in passages close to the spark plugs where combustion occured.
So you never saw the oem gauge get near the red mark before you did the coolant change? BTW that gauge is not completely useless, as some implied. you just have to know the calibration, shown in the FAQs. If it moves from normal, something is wrong.
I think this means you had the caps reversed until now, the one with a spring on the filler neck, and the one on the t-stat housing the plain cap with no spring, correct? That means you had no pressure in the system, and with just water, it would boil at 212F, and with 50% antifreeze, 224F. The pressure cap would seal the system, but there was no inner seat for the inner seal to contact. And the simple cap on the t-stat hsg would leave an open path to the overflow tank, for when the coolant got hot. You were likely doing a lot of local boiling in passages close to the spark plugs where combustion occured.
So you never saw the oem gauge get near the red mark before you did the coolant change? BTW that gauge is not completely useless, as some implied. you just have to know the calibration, shown in the FAQs. If it moves from normal, something is wrong.
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I was going off memory, it had a zero psi cap on the filler neck, and the pressurized cap on the AST.
I replaced both with 13PSI caps (the zero psi cap was lost..long story.)
I would have the temp gauge spike and then drop, spike, then drop, randomly while driving. This never seemed to happen at idle, or even holding the RPM's at 3,000 for fifteen plus minutes.
The car started blowing the upper small AST hose off before I switched both caps out. So I kept adding coolant to the system when the car was cool, until it got to the point where when cold I didn't have to add anything, maybe an ounce or two. (At this point I bought a fuel injection hose clamp to keep that AST hose from flying off.) At that point I took it for a drive, and sure enough, same symptoms repeated. Temp would spike, and then drop, spike, then drop. My theory is the combustion gasses are pressurizing the coolant system when the car is under load, and causing those hot gas pockets.
During this drive, out of nowhere the upper rad hose exploded. Car is down until tomorrow when the upper rad hose comes in. I think the pressure from the gas in the system caused the hose to rupture, but I could be wrong. I need to pressure test the system after I get that hose on.
I noticed none of this happened until I added a bottle of prestone radiator flush to it. Any chance this could have damaged the coolant seals? The car drove fine for 300~ miles with zero temp spikes. This is just something that could be related, I'm not sure. I also replaced the thermostat.
1) did it occasionally spike up near the H mark all the time you owned the car?
2) per the FAQ, did you very slowly add the coolant when you changed it? Otherwise you may trap air during a rushed fill.
If it's a small leak, the ast should purge it out.
Normally, on a cold start, the upper hose stays cold until the t-stat opens above 180F. After a drive, that hose should be too hot to hold.
I agree, looking like an o-ring issue. Many shops have a simple sniffer to detect exhaust in the overflow tank. Simple cheap critical test.
I did not spike from the time I bought it and drove it a few states back home, until I added the radiator flush. Not saying that's the cause of it, but that is when I noticed it sometime after when it started happening.
I believe I added the coolant slowly enough. Before I took it on that drive and it blew the upper rad hose, I had tried to fill it twice that day, and it got to where it would only take an ounce or two of coolant..It never smoked, either. But I'm still leaning towards coolant seal.
Replaced the coolant hose, rented a pressure tester, pressure tested the system on the AST, it held 14PSI for over a minute, then I heard a small hissing on the filler neck, the plastic piece has a hole in it apparently. However, that's the least of my worries, I started it up after filling it up, and see this:
Granted, the car hasn't been started since Friday, but it spat out that steam for about 30 seconds, at least on startup. Looks like the coolant seal to me. Car idled for half an hour and didnt go above 211, though, but thats no news, it would only spike when driving. Thoughts? looks like the coolant seal to me, terrific, looks like rebuild time.
I had the regular zero psi cap, but lost it (long story.) ...
Being nit-picky here, but it is not a ZERO psi cap, its a non-relief cap, which will theoretically not release coolant under any pressure the cooling system is likely to see.
clouds of non stop smoke and coolant level sensor going off are dead giveaways, a little steam on startup could be normal for an old rotary
As far as I know its the original motor, 20k on it, compression is good (though that's irrelevant if we are talking a coolant seal problem, obviously), but that video was the startup yesterday. Did the same thing today, though not as bad, takes a few seconds of the car running for it to start, then it will clear up.
Still working on bleeding the air out of the coolant system, but when I pressure tested the system via the AST, it held at 14 like I mentioned for at least a minute or more until that hole in the black plastic on the filler neck showed itself. If a coolant seal was damaged/compromised, about how quickly should it show pressure loss on the gauge?
If a coolant seal was damaged/compromised, about how quickly should it show pressure loss on the gauge?
I haven't seen a spec for this. I've only seen a few different parameters to confirm that it's sealed. I used Pineapple racing's test (air up to 20psi and let sit for 1 hr) when I had my motor out. When it was in the car with radiator and everything else connected, I pressurized it to 14psi and let it sit for a few hours. I was only able to pass this test after I chased down all of the small leaks I had.
Car was full on coolant, started it, let it run, it was again dripping coolant out of the overflow. Took it to the auto parts store a few miles away, temps never got above 214 on the AEM gauge, but when I got back into the car, and turned the key to ON, the low coolant buzzer went off, started the car up, temps were perfectly normal, buzzer went off about ten seconds later. Got the car back, OEM gauge started to move above the 1/2 way point. Cut the car off since I was home anyway.
Went out to check after two hours ish, removed the filler cap, car did not need any coolant added to it.
It can literally sit and idle with zero overheating or temp spikes, but the second you drive it, that's when it starts.
Just did the block weld treatment, will report back with that tomorrow. Made sure the system didn't have any antifreeze. I wasn't particularly thrilled to do this, but if it buys me enough time to get the car to RotorSports, then it will have done it's job.
Car was full on coolant, started it, let it run, it was again dripping coolant out of the overflow. Took it to the auto parts store a few miles away, temps never got above 214 on the AEM gauge, but when I got back into the car, and turned the key to ON, the low coolant buzzer went off, started the car up, temps were perfectly normal, buzzer went off about ten seconds later. Got the car back, OEM gauge started to move above the 1/2 way point. Cut the car off since I was home anyway.
Went out to check after two hours ish, removed the filler cap, car did not need any coolant added to it.
It can literally sit and idle with zero overheating or temp spikes, but the second you drive it, that's when it starts.
Just did the block weld treatment, will report back with that tomorrow. Made sure the system didn't have any antifreeze. I wasn't particularly thrilled to do this, but if it buys me enough time to get the car to RotorSports, then it will have done it's job.
When you said "Car was full on coolant.." was it at the full mark on the dip stick ?
What is the "block weld treatment" ?
Did you do a pressure test, to see if it would hold pressure?
When you said "Car was full on coolant.." was it at the full mark on the dip stick ?
What is the "block weld treatment" ?
Did you do a pressure test, to see if it would hold pressure?
The coolant overflow was full to the point it was overflowing. The blockweld treatment is essentially the use of one of a few different types of block sealants that you add to a cooling system after you've flushed out all the coolant from it and are running just water. You add two bottles of it, top the car off with water, let it run for half an hour, then shut it off and let it sit overnight. This draws the sealant in from the cooling system and forms a seal where the problem is.
It is by no means a proper solution, or a permanent one. However, if it works, I'm hoping it will buy me enough time to get the car to Rotorsports for a proper teardown and replacement of the coolant seals. People have had mixed success with it from what I've read. I'll find out by tomorrow.
Yes, I did pressure test the system. It does have a small leak. My theory on the issue is, like I've said, is that when the car is under load/being driven, exhaust gasses enter the coolant system and cause gas pockets, which is causing my temps to spike. It won't overheat on its own if it just sits.
Anyway, I'll see tomorrow if it fixed the problem. By no means am I expecting this to be permanent, but hopefully it will be the temporary fix I need to get the car to where I need to take it when I'm able.
Hope the sealant works ... it worked for me on an old car with a radiator leak.
You should always used the expansion tank dip stick when filling with coolant. It has hot & cold marks on it, and it provides an airspace at the top to allow the heated coolant to expand into the tank, once 14 psi is the pressure. About 15-20 oz is the level change. Filling to the top, cold, will always cause an overflow.
Hope the sealant works ... it worked for me on an old car with a radiator leak.
You should always used the expansion tank dip stick when filling with coolant. It has hot & cold marks on it, and it provides an airspace at the top to allow the heated coolant to expand into the tank, once 14 psi is the pressure. About 15-20 oz is the level change. Filling to the top, cold, will always cause an overflow.
Took the car on a sixty mile trip today, Temps never got above 211, this is in stop and go traffic and high heat of the day. Mostly the temps hovered around the low 200's. No temp spikes. So, it looks like I was right, the car has a bad coolant seal, which requires a rebuild. Hopefully this "fix" holds long enough to get the car there.
08-30-19, 01:43 PM
