For some reason my cars coolant overflows under hard acceleration and causes belts to slip. It also looses coolant under normal driving. The car does not miss at all and no water is in the oil, and the car does not smoke at all. I recently replaced my 3rd set of headgaskets which appear to burn the water pockets. I thought it was an overheating issue so I replaced my water pump with a flow cooler water pump, Fluidyne radiator, Mr Gasket therm. 180 and new hoses, and wired my fan on high. Took my car to the dyno with a new set of Mr Gasket ultra headgaskets. But as soon as the car went to high rmp the water started to overflow thru the coolant rec. tank and radiator cap. We came to the conclusion that it is not a cooling issue or gasket issue. We thought the block may be worped or cracked so I tried a can of A&W block sealant but the problem is still there. The only thing I can think of is that the block may be worped I do have arp head studs on the car. I have had my heads resurfaced and pressure tested so I dont think the problem is in the heads. I am totally puzzled and tired of the problem. The machine shop says that they can deck my block but it would have to be completely disassembled. I would hate to do that without trying everything else to fix the problem fist. I am tires of taking my car apart. 
coolant overflow under boost!!!!!!!
- Thread starter Danny's 94Cobra
- Start date
Dan, you've tried everything I would have suggested so far. But lets think about this... what parts of the car see boost? The inlet tube, TB, upper intake, lower intake, intake port on the head, and the cylinder. In order for you to have pressurized coolant it has to be getting that pressure from somewhere, and the only place where boost and coolant are in the same area is the lower intake (its not crack or anything right), the head, and the block. It has to either be getting past a gasket, or through a crack somewhere. As for the warped block the only real way to check it is as you described, however if the machine shop has a machinist straight edge that is short enough you "may" be able to lay it down across the deck surface and use a feeler gauge and see if its warped that way. If its warped bad enough it WILL show up with this method. Just keep re-positioning it around the deck surface and check as many areas as you can. I'd at least try it first before doing a tear down. I don't know what the max allowed tolerance is though, but the machine shop should. Good luck! I know it sucks when you are tyring to fix a problem and no matter what you do its still there. I went through this with my tranny and rear end.
If you are running iron heads there is a chance during tightening down the heads a few times you might have cracked one of them. Just a thought. My neighbors car had this happen to him so it's fresh in my memory. If not then it looks like the block will be coming out.
BlueOvalStangGT
Active Member
Sorry I had not replied just got back from the track my friends Kenne Bell 03 Cobra covertible ran a 10.30 with no nos probably in 9's with the nos. I have not checked my intake maybe the problem is there. How do I go about checking that? It also appears the car looses water even if not under boost just normal driving and it appears problem is getting worse.
A pressure test by a dealer might help diagnose the problem as well as you will be bale to see where it is coming from.
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