psu_Crash Posted April 27, 2009 Report Share Posted April 27, 2009 (edited) Ok so last fall I blew a head gasket and over the winter changed it out with an Ajusa. Brought it through 5 complete heat cycles without driving it over a week's time, and retorqued. Went for a few easy rides this spring and then retorqued again. Started boosting to about 12 psi for a week or so then retorqued a final time. The head was brought to a shop to check for any cracks and to make sure it's flat while it was apart. Ever since doing all of this and finally feeling safe to run it at 14 psi it blows coolant out the overflow. Compression looks great across the board but i know a head gasket will not always show there. I can drive it forever and not have to put a drop of coolant in if I stay off boost. I can't push more than about 7psi without it dumping out the overflow, like up to almost emptying the system in a couple miles. Temp comes up to just under 210 on hard runs but it doesn't get any higher. Mainly because I take short hard runs and then have to top off the coolant. Just put a new radiator cap on and that made no difference. Also once I get it back home and shut off I can hear bubbles in the overflow tank for a minute or so even though it doesn't continue to dump fluid. When it cools down it will suck coolant out of the overflow back to the radiator. Possibly boiling somewhere?? I am at a loss as to what could cause this besides a head gasket issue... again. Sure looks like I am going to be pulling the head. Any pointers or ideas? What am I doing wrong here?? Edited April 27, 2009 by psu_Crash Link to comment Share on other sites More sharing options...
JustPaus_88TSi Posted April 27, 2009 Report Share Posted April 27, 2009 Definitely pressurizing the cooling system. Have you noticed white smoke from the exhaust when this happens? Wondering if maybe the head really is okay, but the block has a hairline crack along the coolant port/head stud area. Link to comment Share on other sites More sharing options...
chiplee Posted April 27, 2009 Report Share Posted April 27, 2009 don't have time to read your post but just from the thread title I can tell you that when this happened to me it was a cracked block. I replaced a gasket, then a head and then a block. Lots of extra work went into "hoping" it wasn't the block. Try not to do what I did. Link to comment Share on other sites More sharing options...
Elkidmino Posted April 27, 2009 Report Share Posted April 27, 2009 ^^ The above worries me because I had this same problem. What I found was a blown gasket under the TBI, the bowl gasket. I replaced the head and went MPI but have yet to boost it to see if I still have this problem. I'd say check the bowl gasket first, then HG, then head and go from there. Link to comment Share on other sites More sharing options...
StarquestRescue Posted April 27, 2009 Report Share Posted April 27, 2009 I would recommend a leak down test it to try and identify which cylinder is pressurizing the coolant system. In this case pulling the cam out so you can test at bdc with 90 psi shop air plumbed directly to the cylinders would probably work best. If you can narrow it down to one or two cylinder it would be easier to find the problem if you pull the head. Could a leak in the magna intake be letting boost in to the cooling system? Probably a along shot. Link to comment Share on other sites More sharing options...
Technology Posted April 27, 2009 Report Share Posted April 27, 2009 ^^ The above worries me because I had this same problem. What I found was a blown gasket under the TBI, the bowl gasket. I replaced the head and went MPI but have yet to boost it to see if I still have this problem. I'd say check the bowl gasket first, then HG, then head and go from there. He's already got MPI. Maybe starquestrescue is on to something there with the magna. I'm experiencing an external leak from the hose under the magna, and I see wet spots above the flange, right under the valve cover, that might be the VC leaking somewhere, but it's not making me happy. Anyway, did you ever check the flange for flatness? When I bought mine, it was warped from welding and I got it flattened enough to install. What you might also do is buy or make an adaptor for the radiator cap so you can pressurize the radiator. Can't do too much, but maybe you can hear air/coolant leaking out somewhere. Other than that, do what others said, a leakdown test, or just a pressurized cylinder and listen closely. Link to comment Share on other sites More sharing options...
psu_Crash Posted April 27, 2009 Author Report Share Posted April 27, 2009 I don't believe I am smoking at any time when it does this. At least no one following me has ever told me if it does. Chip, You terrify me! I cracked the last block and this engine only has aprox 4k miles on it since a full rebuild. Block was completely checked out at the shop then, but who knows what kind of damage I have done to it since ... I have access to equipment for a leakdown test, and a fitting for the radiator. So tomorrow I will give that a shot. 90 psi to the cylinders, how much psi should be used on the radiator? Tech, I did check the flange and all is well there. I thought the same, thing that I was leaking pressure at the gasket since it was leaking oil before. But I changed it out and now it doesn't leak a drop. Link to comment Share on other sites More sharing options...
jolyrgr Posted April 28, 2009 Report Share Posted April 28, 2009 (edited) I had one do the same thing. It had blown the intake manifold gasket, and pressurized air was getting into the coolant passage. Might be worth a check out. JR EDIT: this was also on a modded Magna intake, right around where the rear coolant passage was modded. Edited April 28, 2009 by jolyrgr Link to comment Share on other sites More sharing options...
mistapickles Posted April 28, 2009 Report Share Posted April 28, 2009 I had the same thing happen to me, three head gaskets and two heads later, it was a cracked block, YEAH. It didn't blow steam until I let it warm up too long one night. When I pulled it apart the cylinder walls were steamed clean, not a lick of oil on them, so maybe when you pull the head again you can look for a pristine almost chrome cylinder or two or four, with absolutely no oil on them at all. Link to comment Share on other sites More sharing options...
Technology Posted April 28, 2009 Report Share Posted April 28, 2009 Well, try and eliminate all possibilities before jumping to the cracked block conclusion. The cooling system only ever reaches 13-14psi, so you have to keep it kindof low when testing. You could also possibly remove the camshaft and pressurize the intake manifold only. Maybe pull one of the vacuum nipples and screw in some kind of air fitting, then put about 20-25psi in it, listen for bubbling. Link to comment Share on other sites More sharing options...
psu_Crash Posted April 28, 2009 Author Report Share Posted April 28, 2009 (edited) Borrowed a pressure tester for the coolant system and pumped it to 15 psi and walked away. Came back 15 minutes later and it hadn't moved at all. Pumped it to 20 and the same result, but at 25 psi I found that one of the clamps for my heater core hose wasn't tight enough Anyways that looked good. Took the fitting from my compression tester and fitted it to the air compressor at 90 psi. One cylinder at a time, listened and watched ... nothing and they all held the pressure only bleeding off very slowly. Quick comp check was 130 across the board. Went for a quick ride and beat on it at 12 psi. Came back let things cool down, checked the coolant and was competely sure it would be low ...... still full. WTH !?? I didn't hear the usual bubbles in the overflow either. I am not even close to convinced that it just fixed itself so I ordered a new head gasket. In the next few days I'll have it out running 15psi and see what happens. It ALWAYS dumped some coolant under boost ... I don't know what pressurizing things did to it, but it somehow helped?? P.S. When I pulled the cam to get all valves closed there were 2 cam tower bolts (not on the same tower) that I could have taken out with my fingers!!! Not sure how that happened because I know they were all torqued to spec. Either way something good came of this! Edited April 28, 2009 by psu_Crash Link to comment Share on other sites More sharing options...
strang3majik Posted April 28, 2009 Report Share Posted April 28, 2009 Does the mileage by any chance turn backwards? That would explain it right there. Link to comment Share on other sites More sharing options...
psu_Crash Posted April 28, 2009 Author Report Share Posted April 28, 2009 Does the mileage by any chance turn backwards? That would explain it right there. HA HA! No luck there. The build only has a few thousand miles on it anyways. Link to comment Share on other sites More sharing options...
dmyers151 Posted April 28, 2009 Report Share Posted April 28, 2009 P.S. When I pulled the cam to get all valves closed there were 2 cam tower bolts (not on the same tower) that I could have taken out with my fingers!!! Not sure how that happened because I know they were all torqued to spec. Either way something good came of this! Loctite dude. I was so paranoid of my cam tower bolts backing out, I used RED Loctite on all of them, I think it was one step below permanent. Link to comment Share on other sites More sharing options...
Indiana Posted April 29, 2009 Report Share Posted April 29, 2009 Each time you lost coolant what did you do? Did you remove the cap and fill the radiator completely up to the top so no more could be added then put on the cap and the over flow was at the upper mark? When the motor gets hot its completely normal for it to puke coolant out because the radiator was just too full. If it happens quickly that does send the coolant into the bottom of the overflow jug and it would come out with some force after it over come the 16lb radiator cap and that would make some be lost. Can't comment on the bubbles, maybe it was just trapped air or when the motor cooled down your hoses to the overflow do not seal 100% so it could suck in some air and not draw back in coolant. Link to comment Share on other sites More sharing options...
StarquestRescue Posted April 29, 2009 Report Share Posted April 29, 2009 Took the fitting from my compression tester and fitted it to the air compressor at 90 psi. One cylinder at a time, listened and watched .. The radiator cap was off and your ear to the opening? When i checked my na truck a while back it pushed the coolant right out of the radiator and that was with only 35 psi. It does not push it out the overflow tank either or boil over. I just need to top it off every so often. On 3000gt turbos they have problems with head lift on the high horsepower cars. I don't think your quite to that level yet, but any detonation will send the cylinder pressure sky high. I hope you get it worked out. Link to comment Share on other sites More sharing options...
psu_Crash Posted April 29, 2009 Author Report Share Posted April 29, 2009 The radiator cap was off and your ear to the opening ? Sure was. Indiana you may be onto something. Overflow is usually about half full at a cold start and I do fill the Rad right up just about to where it can't take any more, but when it dumped coolant a few of the times I could not see any water in the radiator and it took aprox half a gallon to fill it. As for the intake gasket I am sure that is sealed up good. I just replaced it and took care to use a layer of gray rtv all around all of the ports. New studs and locknuts all torqued to spec and checked for retorque after a few rides. This is very annoying because the guys at the dyno will not be happy if I dump coolant all over, and I am in need a a good dyno tune to dial this beast in Link to comment Share on other sites More sharing options...
Technology Posted April 29, 2009 Report Share Posted April 29, 2009 Mine puked a bunch of coolant when I first filled it up and let it get hot, but it hasn't done anything like that since. If your head and block aren't cracked, what are the possible places air would be forced into the cooling system? The intake manifold is all i can think of. Link to comment Share on other sites More sharing options...
psu_Crash Posted May 1, 2009 Author Report Share Posted May 1, 2009 OK guys. So in an act of desperation I pulled the radiator. It was supposedly serviced by a local shop and said to be good. My line of thinking is that if the radiator is plugged up at all then at higher RPM it will not flow enough and build pressure that would be released out the cap. Right? Had the Rad out and dumped water in the top. Now correct me if I am wrong but shouldn't the water run right out the bottom as fast as I can dump it in the top? Mine does not... Link to comment Share on other sites More sharing options...
Indiana Posted May 1, 2009 Report Share Posted May 1, 2009 Well sort of, you can pour in some muratic acid then lay it flat with the cap on and let it soak for an hour or so, it will react with calcium and the copper and brass and clean it up. Rinse it out though, it will make steel rust but it won't cause rust in the radiator. You can get a gallon of it at a home improvement store for maybe $6, it also will clean your concrete or bricks and kill grass so watch out, sometimes its called pool cleaner or sidewalk cleaner it will have different labels. You'll see what it does when you pour it in, don't inhale it either. Link to comment Share on other sites More sharing options...
psu_Crash Posted May 1, 2009 Author Report Share Posted May 1, 2009 Guy at the store told me 3 times how dangerous this concrete cleaner is. He also said to make sure I dilute it. I told him it wasn't for the sidewalk. I know it will let off a nasty gas too, chlorine i believe. Wish me luck. :sweatingitout: Link to comment Share on other sites More sharing options...
Shelby Posted May 1, 2009 Report Share Posted May 1, 2009 if you have air pressure back flush the rad from the bottom to top, the fins will plug at the top of the rad , blowing water/air back wards from normal flow dir can break a lot of the blockages loose and out lay rad flat or nearly flat , it's the water that actualy breaks the crud loose not the air pressure but a combination of the two Link to comment Share on other sites More sharing options...
Recommended Posts