I am thinking a Coolant Leak

[teg21]

Ok well here is the problem for the past couple of weeks I have been trying to diagnose a coolant problem. I have changed the thermostat and the radiator cap (with a 13psi and I had a 16psi but it was all advance had) and I did my headgasket about 3 months ago with the metal mitsu and arps.

On the highway my coolant temps get high after anywhere between 30 mins to 2 and a half hours of driving. If I run the car hard for a couple of pulls they also tend to get high usually about 230. Sometimes they will get above this and I pull over let it cool down and sometimes they will go back down.

My car also has the problem of bubbling out the overflow tank on some occasions when it gets hotter. I have checked for leaks numerous times and have never seen anything leak. Could coolant be vaporizing before it hits the ground when the engine is hot? Could it be the cause of another problem besides a leak?

I don't have access to pressurized air which makes it harder to check for leaks. But I am thinking of just going ahead and replacing all my hoses. Any help or suggestions on what else could be the problem would be appreciated. Thanks.

P.S.

My mods are in my profile but basically 16g, buschur front mount, 550s, etc. running 15psi(i am also having a problem with faulty knock, hopefully the new knock sensor will fix it)

 

[Doug99RS]

I would think that the radiator is ok. You should have mentioned a new radiator was in the car.

Looks like your left with water pump and possible head gasket sealing issues.
Doug

 

[teg21]

Yeah I thought I did but I guess not. Yup seems like the head or the water pump I'm on way to go check the torque on the head studs so I'll let you know. Thanks for the help.

 

[jpolizo]

Ya know, there seems to be a good deal of it can't be this because blah or it can't be that because umptyfudge. The bottom line is that psyching this out is not working. I'd get real methodical here and check the hell out of everything without making any assumptions whatsoever.

What I've found in debugging computer programs is that the problem is almost always sitting under my nose but I've convinced myself that it can't possibly be what it is.

 

[teg21]

Yeah well that would work except that most of the stuff I ruled out I have replaced: thermostat, radiator cap, overflow bottle. I think it is a leak and the leak is probably in the head. I had the coolant system pressurized and no leaks and I had the head gasket checked.

I don't understand what you think I am ruling out? I have narrowed it down to the waterpump and the head. I think you have to rule stuff out in order to solve a problem if you test everything in the car you are going to be there for awhile. Also, I don't think I have made assumptions, things have been tested and replaced.

 

[jpolizo]

OK, so you pressurized the coolant system and there are no leaks; that means it's not leaking through "the head" when you put modest pressure into it. You're not getting exhaust gas into the cooling system because of this test that looks for exhaust gasses. So that means high pressure in the cylinders is not getting into the cooling system. You're not getting water in your oil. Where is this theoretical leak going that doesn't effect compression, doesn't reveal a leak under pressure in either direction, and leaves no trace of itself anywhere?

 

[teg21]

Originally posted by jpolizo
OK, so you pressurized the coolant system and there are no leaks; that means it's not leaking through "the head" when you put modest pressure into it.

Wrong! This does not mean no coolant is leaking through the head. When the system is pressurized like that it usually won't show up a bad head gasket or a warped head it will usually show leaks in hoses.

Originally posted by jpolizo
You're not getting exhaust gas into the cooling system because of this test that looks for exhaust gasses. So that means high pressure in the cylinders is not getting into the cooling system.

I am thinking it is a minor leak which is leaking into the combustion chamber. Since there is no white smoke and I am not losing much coolant there is not much entering just enough to cause overheats.

So if you don't think it a warped head and its not the radiator cap, thermostat, overflow bottle, a leak in a hose, a clogged radiator, then what do you think it is? Also, a warped head wouldn't necessarily cause bad compression it would lower compression but not too significantly and my compression 4 months ago was in the 150s.

 

[jpolizo]

Originally posted by teg21

If I run the car hard for a couple of pulls they also tend to get high usually about 230.

Slow leak, eh?

OK man, sounds like you've got it all figured out.

 

[teg21]

I don't understand what you are talking about. It seems like you are just telling my that I am wrong. What would be your suggestions on diagnosing the problem. Do you have any ideas on what it could be if you don't think it is a problem with the head?

Also I think on a hard pull if the head was warped this would cause the car to overheat faster since I would be pulling more coolant into the combustion chamber(if this is the problem).

 

[Doug99RS]

OK... so I've read all of this thread and don't remember half of what's in it except that there's been alot of components ruled out based on the concept of how they work and when they typically will exhibit problems. BUT... what I don't see, or maybe it's just I don't remember, is how much coolant has been getting added.

The topic of the thread is "Coolant Leak". Now, while sitting around and ONLY thinking about the possibilities will not actually diagnose and repair the problem it IS important to at least understand how each component works and how a failing condition becomes evident to the driver.

First off... if there is a coolant leak (externally, into combustion chamber, in to oil, or in to the heater box) then how much coolant has been added over a certain period of time?

Second... the coolant leak itself, while leaking, will NOT cause the engine to over-heat. Over-heating in this particular scenario would only occur once the coolant level has dropped down below a certain level. So... the question is... when it's "overheating" how much coolant do you add when it cools down?

Next... Do you have a front mount on this thing? It may be possible that the front mount is preventing enough air from cooling down the radiator.

Next... when you had the coolant system pressurized did they remove the spark plugs? Leaving the spark plugs in, in some conditions, may be the sealing factor that will prevent a pressure drop. Remove the plugs and check for a pressure drop.

Is the belt tension tight on the water pump? You mentioned hard pulls... if the belt is slipping on these pulls then the pump is not spinning at 100% efficiency.

The coolant pressure tester is designed to apply a specified amount of pressure. The radiator cap determines how much pressure the technician should apply to the coolant system. So... if the pressure tester is only pumped up to 10 psi then you're not allowing enough pressure to build up.

Pressurizing the coolant system WILL test the headgasket integrity as well. It recreates the same pressure as a fully operating engine only without the heat factor. A headgasket may only weep a small amount of coolant with no pressure but will POUR coolant once pressurized by the tester or the engine itself. A warped head, given the right conditions, will exhibit a coolant leak when pressurized with the tester.
I guess the most important thing to say about all that is that the coolant pressure tester will recreate the same amount of pressure as the engine will. So if you can't force a leak with the pressure tester, you probably can't force it by running the engine.

Did you have a cooling problem four months ago when you ran your compression check? If not... then the fact that you have an over-heating condition now is proof enough that conditions in your vehicle have changed. Likewise... a compression check again MAY prove that something has. It may be a waste of time... or it may answer all these questions that have been flying around.

Finally.... the key points are this... the coolant pressure tester recreates the same pressure as the engine creates, low flow throughout the coolant system will increase temps as will low air flow through the radiator fins, pressurizing the coolant system with the spark plugs still in MAY mask the true culprit, and is the coolant mixture 50/50? Pure coolant will NOT protect the engine as well as a 50/50 mix.
Doug

 

[jpolizo]

Originally posted by Doug99RS
OK... so I've read all of this thread and don't remember half of what's in it except that there's been alot of components ruled out based on the concept of how they work and when they typically will exhibit problems. BUT... what I don't see, or maybe it's just I don't remember, is how much coolant has been getting added.

The topic of the thread is "Coolant Leak". Now, while sitting around and ONLY thinking about the possibilities will not actually diagnose and repair the problem it IS important to at least understand how each component works and how a failing condition becomes evident to the driver.

First off... if there is a coolant leak (externally, into combustion chamber, in to oil, or in to the heater box) then how much coolant has been added over a certain period of time?

Second... the coolant leak itself, while leaking, will NOT cause the engine to over-heat. Over-heating in this particular scenario would only occur once the coolant level has dropped down below a certain level. So... the question is... when it's "overheating" how much coolant do you add when it cools down?

Next... Do you have a front mount on this thing? It may be possible that the front mount is preventing enough air from cooling down the radiator.

Next... when you had the coolant system pressurized did they remove the spark plugs? Leaving the spark plugs in, in some conditions, may be the sealing factor that will prevent a pressure drop. Remove the plugs and check for a pressure drop.

Is the belt tension tight on the water pump? You mentioned hard pulls... if the belt is slipping on these pulls then the pump is not spinning at 100% efficiency.

The coolant pressure tester is designed to apply a specified amount of pressure. The radiator cap determines how much pressure the technician should apply to the coolant system. So... if the pressure tester is only pumped up to 10 psi then you're not allowing enough pressure to build up.

Pressurizing the coolant system WILL test the headgasket integrity as well. It recreates the same pressure as a fully operating engine only without the heat factor. A headgasket may only weep a small amount of coolant with no pressure but will POUR coolant once pressurized by the tester or the engine itself. A warped head, given the right conditions, will exhibit a coolant leak when pressurized with the tester.
I guess the most important thing to say about all that is that the coolant pressure tester will recreate the same amount of pressure as the engine will. So if you can't force a leak with the pressure tester, you probably can't force it by running the engine.

Did you have a cooling problem four months ago when you ran your compression check? If not... then the fact that you have an over-heating condition now is proof enough that conditions in your vehicle have changed. Likewise... a compression check again MAY prove that something has. It may be a waste of time... or it may answer all these questions that have been flying around.

Finally.... the key points are this... the coolant pressure tester recreates the same pressure as the engine creates, low flow throughout the coolant system will increase temps as will low air flow through the radiator fins, pressurizing the coolant system with the spark plugs still in MAY mask the true culprit, and is the coolant mixture 50/50? Pure coolant will NOT protect the engine as well as a 50/50 mix.
Doug

 

[Doug99RS]

Well????

 

[teg21]

Fisrt off, sorry my internet has been down so I haven't been able to get online.

Originally posted by Doug99RS
BUT... what I don't see, or maybe it's just I don't remember, is how much coolant has been getting added. [/B]

If I drive on a 45 minute drive I will have to add about 10 to 12 ounces.
Just normal everyday around driving in town I will have have to add about the same amount every 2 days.

Originally posted by Doug99RS

Second... the coolant leak itself, while leaking, will NOT cause the engine to over-heat. Over-heating in this particular scenario would only occur once the coolant level has dropped down below a certain level. So... the question is... when it's "overheating" how much coolant do you add when it cools down?

If the car gets hot say about 230-240 water will bubble out of the overflow this will cause me to add more coolant than usual, probably around a gallon. If the needle is just climping while driving getting around the 200-210 range no coolant needs to be add except what stated before.

Originally posted by Doug99RS

Next... Do you have a front mount on this thing? It may be possible that the front mount is preventing enough air from cooling down the radiator.

I have a buschur front mount and didn't have a problem before with cooling. I have since hooked up my a/c fan to run constantly with the main fan and I am still have cooling issues. I don't think there would be an airflow restirction if I have both fans running but what do you think?

Originally posted by Doug99RS

Next... when you had the coolant system pressurized did they remove the spark plugs? Leaving the spark plugs in, in some conditions, may be the sealing factor that will prevent a pressure drop. Remove the plugs and check for a pressure drop.

They left the spark plugs in when they pressurized the system I'll see if I can go back there and have them pressurize it again with the spark plugs out, if you think it would be help

Originally posted by Doug99RS
Is the belt tension tight on the water pump? You mentioned hard pulls... if the belt is slipping on these pulls then the pump is not spinning at 100% efficiency..

The belt seems to be tight to the feel I haven't checked to see if it is loose with a ruler but I'm pretty sure I am alright there. Seems to be tight.

Originally posted by Doug99RS
The coolant pressure tester is designed to apply a specified amount of pressure. The radiator cap determines how much pressure the technician should apply to the coolant system. So... if the pressure tester is only pumped up to 10 psi then you're not allowing enough pressure to build up.

They pressurized the system to 15 psi and the pressure didn't drop after about 30 seconds to a min.

Originally posted by Doug99RS
Did you have a cooling problem four months ago when you ran your compression check? If not... then the fact that you have an over-heating condition now is proof enough that conditions in your vehicle have changed. Likewise... a compression check again MAY prove that something has. It may be a waste of time... or it may answer all these questions that have been flying around.

I did not have overheating problem when I checked the compression before. Why would it matter if the compression is different now, than 2 weeks ago?

Originally posted by Doug99RS
Finally.... the key points are this... the coolant pressure tester recreates the same pressure as the engine creates, low flow throughout the coolant system will increase temps as will low air flow through the radiator fins, pressurizing the coolant system with the spark plugs still in MAY mask the true culprit, and is the coolant mixture 50/50? Pure coolant will NOT protect the engine as well as a 50/50 mix.
Doug

I guess I need to go back and get the system pressurized with the spark plugs out and see how that turns out. I was running a 40/60 coolant/water mix and then I switched to that stuff in a can you can buy at Advance Auto that says it will lower your coolant temps up to 28 degress. Both mixtures didn't seem to help any and I also tried straight coolant they also didn't help.

 

[teg21]

sorry about the last post my computer frooze and I guess sent what I had been typing and I couldn't get back online to change it.

Also thanks for all the help so far Doug you have made some good points.

 

[teg21]

Ok speaking about a possible leak here is what I feel on that just trying to whore some posts .

I have no white smoke meaning it doesn't seem like I am burning coolant unless its not enough to make smoke, I have no oil in coolant, no coolant in oil. There are no drips coming from under my car at idle or off so it seems if its a leak it must be hidden and burning up before it hits the ground. But then again the pressure test came out negative for leaks but i am still a little skeptical.

 

[teg21]

Doug you have any other ideas?

 

[Doug99RS]

Originally posted by teg21


I did not have overheating problem when I checked the compression before. Why would it matter if the compression is different now, than 2 weeks ago?

The reason why I suggested the compression check again is because obviously something has changed between the time you checked it last and now (now it's over-heating/losing coolant). So what I'm getting at is that the compression check with the plugs out of it now may show a pressure drop in the coolant system or in compression because the head may be cracked, headgasket blown or something of that nature.

My example could be explained better maybe like this... your car starts one week, the battery tests good. The next week it is slow to crank and the battery light comes on while driving. Do you still want to work off of your findings that are old when trying to diagnose a problem that has shown up since then? A compression check is quick and easy as well as the coolant pressure test.

Without the car in front of me I'm really tapped for possibilities. I think everyone involved in this thread has brought up all the possibilities. It's just a matter of finding which one was the actual cause. If the compression test and coolant pressure test reveal nothing new then I really don't now where to direct you from there. However, if you do decide to pull the head, at least take it to a machine shop and have them pressure test the head for cracks.

Outside of that... I've really run out of options since everything seems to be new or "tested". Only other place to check would be the heater core. Maybe it's spewing coolant in to the heater box. But normally it would either dump out on to the floor or out the a/c drain and on to the ground, which you'd see.
Doug

 

[teg21]

Well thanks for the advice. The compression was 150s with no overheating and then once it was overheating I did another compression test and came out with the 140-140-145-140. I'm not sure if you thought the only compression test I did was the one before it was overheating cause that's what it sounded like.

I am going to go home on the 4th I'm at school now where I can use my friend's garage and all his tools and we are going to pull the head and change the water pump. I will definitely have the head checked for warping and cracks while we have it off the car. I'll also take a look at the heater core to see if that is leaking.

Thanks for all the info and hopefully I'll have this problem fixed in the near future.

 

[Doug99RS]

Yeah, I wasn't sure if you had done another compression check since it started overheating.

Hopefully you'll find your problem. Please re-hash this thread and let us now what you found.
Doug

 

[teg21]

I'll try to let you know after the weekend of the 4th

 

[teg21]

Well we started taking apart the car this weekend but decided not to take the head off yet. We did another compression test and it came out 157-156-156-156 and the leak down test didn't show anything wrong and did not make the coolant bubble so it didn't appear that there was a problem with the head. So we started to take everything off to do that water pump and finally when we take the lower timing belt cover off we find that the balance shaft belt had most fo the teeth worn off and wasn't really turning the pully and the rear balance sharft wasn't lined up correctly. There was also lots of sludge all around the waterpump. We took the water pump off and it looked good on the inside but I am thinking that it was leaking and possible tore the teeth off the belt.

The other reason we didn't take the head off was that on the way I stopped half way through the trip after 2 hours and got some gas cooled my car down and added some coolant. When I got there after about another 3 hours of driving I had again lost a lot of coolant about 20 - 30 ounces. We didn't think there was any possible way that a warped head would cause that much coolant to leak out and not end up in the oil or be visible and since the compression came out good we decided to try the water pump first. So I am going back home next weekend to finish the water pump and change the balance shaft belt and then hopefully she should be working great. I was also getting a lot of knock and I was thinking it was phantom knock or a bad knock sensor but I think we found that problem (the balance shaft belt) I can't wait to get her running again she should be working awesome right in time for the SHOOTOUT . I'll post again when I actually finish and have her up and running but until then let me know any thoughts and if this sounds feasible. Thanks for all the help so far.