hi guys got a problem with my 98 2200 sunfire. the past couple weeks its been boiling/bubbling coolant out of the overflow while driving but mainly when you let it sit and idle with the cap on or off it still does it. so far i replaced the tstat, and water pump. so suspecting i had a bad headgasket i went and bought a re maned head from ebay and got all the gaskets. went to go do my head gasket yesterday and saw that the casting numbers were different on the heads and that the new head wasnt gonna work because 98 was a standalone year for the heads(egr holes,exhaust side of heads different) and that the new one was for 99and up 2200s even though the ebay listing said 98s would work. so i went ahead and cleaned up the original head and reused it, it was saturday and no time to take it to a machine shop. now i have never fully overheated the car in the 2yrs ive owned it but it has ran hotter than normal once and a while. is it possible that the head could be warped/cracked because the car is still boiling over the overflow.
any help much appreciated!


98 Sunfire SE Coupe(beater car)
02 Monte Carlo SS - L67 Top Swap, 3.6 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.7@101.59mph

you should have waited to have it machined. in the end it was just a waste of time.

i know but i needed to have the car running again so i crossed my fingers and ended up screwing myself. if only the ebay seller sent me the right head. n does it sound like my head is warped? there no external leaks or anything


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

I got my head gasket done as well and in the same boat. I just drilled 2 holes in the thermostat and I'm not over heating anymore. The only difference is I have an ecotec. I want to fix it but its the only fix I found for now.

I have replaced several head gaskets without remachining the heads and not had an issue yet. The holes in the t-stat help clear out any air bubbles that get trapped in the head so that is a good suggestion as well. However if the head had a crack in it that you couldn;t see then there could still be an issue with it. I have found that heating them up will help exposed any hidden cracks and determine if that is where the problem is. Unfortunately you have to take the head offf again to do this.


I may be Crazy but I think this will work....Naw I'm just crazy.

so you think the head could have a small crack/cracks that i couldnt see? and thats whats pressurizing the cooling system? before i replaced the head gasket it would boil over alot almost till the rad was empty now it just has slight bubbles and still continues to boil over but not as bad so im guessin its gotta be the head, and the temp gauge gets as high as almost 3/4 of the way up while idling when it starts to boil. i did everything right i know that for sure. leaving the cap off while idling for about 20 minutes coolant shouldnt boil over right? i feel like i never had that problem before all this started happening and i could leave the cap off without coolant boiling over.
thanks for your help so far guys.


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

i had cracks on my ohv near my intake/exhaust valves.

@!#$ i should have looked closer at it. did you overheat your car bad for that to happen?


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

mine did the exact same thing about 6 months ago..all it was was a small crack in the gasket it self and it was letting exast into the water jacket..i took my head off had it shaved..Bought new head set thermostat and head bolts replaced everything back and now it runs like a champ.....Btw when u put it back together did u reuse ur headbolts???

i used new felpro bolts and head gasket torqued everything to spec. so you think its my head thats either cracked or warped?


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

Its possible..the only thing i did diff is have my head resurfaced..

I had this same thing happen to me, I had my head resurfaced too but coolant kept boiling over. Ran it for the longest time with out a thermostat until it started warming up outside then the coolant flowed to fast to cool down so it started getting hot again. Thinking it might have fixed itself I put a thermostat back in it and nope, started to boil over again. Last place I looked was the pressure lines for the cooling system( I guess thats what they are, the small ones that go into the top of the reservoir). Turned out these had a slight clog, looked more like ferret poo when it came out, lol. Made sure those hoses and lines were freed up and where they went into the reservoir as well. And that fixed the problem, after going through 4 thermostats, 2 water pumps, new main hoses, and probably 20 flushes, oh and a few caps too, lol.

hmm ill check those out when i pull it apart again this weekend to put the new head on.i keep my coolant very clean so i dont know how it could clog up though. hopefully the original head is cracked/warped cuz i dont know what else it could be.


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

Yeah, I usually keep my coolant very clean as well but stuff still gets in there somehow, lol. I thought the same thing with the head being warped/cracked(never got it pressure tested, so didn't know for sure). But i'm glad I found the clog before I decided to get another head.

I've seen it a few times where someone installed spark plugs wrong and it would crack between valve and plug hole. Mine did that. I bought the motor from a bone yard and the plugs were hard to put In didn't think much of it they werent cross threaded. It ran for 3 months like yours and then one day blew it out he exhaust and ran like crap.

that could very well be because 2 of the plugs are kinda hard to get in and out and arent cross threaded. im redoing everything this weekend with the correct new reman head and ill take a good look at the old head. ill let ya guys know.


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph

Have you had any luck?

got it all back together with the original head, machine shop cleaned pressure tested and planned the head. it was warped but they made it perfect. car runs like new again


98 Sunfire SE Coupe(DD,beater car)
02 Monte Carlo SS - L67 Top Swap, 3.4 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.6@102.49mph