All right.. So I recently replaced the lower intake manifold gaskets due to a coolant leak in the front of the manifold.. I have edelbrock performer upper and lower.. now, it will overheat. I have replaced the thermostat. 192 and 180 units, tried both. pressure tested system and checked for leaks at 16lbs.. none visible and held pressure. Used a coolant bleeder bucket to attach to the radiator opening and bleed air.. no luck still. replaced head gaskets a few months ago. no water in oil.. what else could I be missing? when I drive it. it stays cold for awhile.. then all of a sudden right up to 260.. then goes down to maybe halfway then up again.??? I am really getting frustrated! let me know anything you can think of.. I really don't want to pull the intake again or do the head gaskets again.. thanks---Mike
Overheating!!!
- Thread starter Raginstang
- Start date
Mike, when does it do all this? Idling, at speed, etc? And how long does it take for the gauge to go up to 260*F (in other words, does it seem feasible with how long it takes to reach that temp and then come back down, or could be be a gauge issue)?
Good luck.
Good luck.
Hey, thanks for the reply. Um, I know its overheating because water fills up my overflow resavoir and blows onto the ground.. and I usually drive a little bit before it acts up.. usually only after I run it hard.. I also feels as if I developed some sort of low speed missfire or something.. car just doesn't feel all the way there or souund it.?
Black1987Stang
Active Member
I bet its from having an air pocket in there somewhere...once my tb coolant hose started leaking so i relieved the pressure with the lever on my cap, hoping that would slow it down, but all it did was dump coolant into the reservior tank and since coolant in the tank theres air in the system, and my car did the Exact same thing, the temp would Jump right up, i refilled the rad. to the top and still did it for 5 minutes but after it ran through the system and i was driving around its fine now....ill never forget that, made me like an hour late for school. I say just top off the rad and drive it around without getting on it and keep ur eye on the gauge. supposedly our heater cores are bad for keeping air pockets in it...now that i think of it, when it happened to me i had absolutely noo heat, once i felt the heat coming back i knew the air was getting out...I heard if u jack up the front and run the engine with the cap off, since the radiator is the highest point it makes all the air come out and go out through the cap. I never ever had a problem with mine or my friends stang like this though.
Diddle.. thanks for you post.. and for replying to some of my others as well! umm.. im with you on the air pocket thing except that I have a device that attaches to the were the radiator cap goes. it is a bucket and you fill the radiator with that bucket attachec and run the car.. it will burp out all of the air and fill it at the same time.. I did that for almost 15 minutes tonite and still it did it!!! and it overheats and pushes water into my overflow till its full then onto the ground! hrmm.. no white smoke either...
just4bob50
Active Member
I am currently having the exacts ame problem. I solved it buy drilling a whole in the thermostat to bleed out air pockets, but I made the holes to big and had to get a different stat. I will say that with the hole there to bleed off the air pockets it stayed at about 165 on the highway and 180 at idle. Believe me your guage will correct almost instantly when there is a temp change, both my factory and SW gauges did the same thing. The new stat I put in is a 180 with a single 1/8" hole to bleed air. on the highway the temps are 180 and at idle around 190. if you dont get all the air out the first time it will probrably take a day or 2 to get them all out.
just4bob50
Active Member
just4bob50
Active Member
I was going to go to a radiator shop and have them do a power flush because it is a sealed system. So when they're done there shouldnt be any air in the system at all. My heat was coming and going as well. No heat at 260 and plenty at 180.
One other dynamic to consider, though a bit unlikely, is that the lower rad hose is collapsing (your noting that it happens after getting on it made me wonder).
You can start to get some funky cavitation issues when that occurs (it is more common on mod motors, but happens with foxes too).
It sounds like you are a good wrench and have some tools at your disposal, so that should help ya get to the bottom of it.
Good luck.
You can start to get some funky cavitation issues when that occurs (it is more common on mod motors, but happens with foxes too).
It sounds like you are a good wrench and have some tools at your disposal, so that should help ya get to the bottom of it.
Good luck.
yeah, thanks Hissin.. I am a ASE cert tech at a local Toyota dealer and I actually did work for Ford for about a year.. nice to have friends in the parts department!! so yeah, I do own a lot of tools since I need them for my job and also Toyota has a ton of Flushing equipment.. Power Steering, Coolant, Trans, Brake Fluid etc.. all work pretty good.. just sometimes with these dang modified cars...things just don't go as easy as the stock Camry with a check engine light 
but I will definetly check the lower hose, though like you said Im sure its probally not. I did however trim the new intake gaskets to match my head, including coolant ports on both sides... maybe somehow I accidently went to far.. although I checked to make sure and I think I would have noticed it..
but I will definetly check the lower hose, though like you said Im sure its probally not. I did however trim the new intake gaskets to match my head, including coolant ports on both sides... maybe somehow I accidently went to far.. although I checked to make sure and I think I would have noticed it..Raging- Same delima here when i first fired up my 393. Temp would shoot up to 260, and hangout. I thought I had filled the radiator too. I removed my top radiator hose, and noticed that the hose was dry. Removed t-stat housing, still no water. Kinked upper hose, and wrapped a rag around my air nozzle and blew air into through the radiator cap, which forced water through the heater core, water pump and out the bypass hose on the t-stat housing. Then I refilled my radiator until coolant was free flowing from the intake manifold where the t-stat goes. Radiator is taller, so should gravity feed. Removed t-stat and boiled to be sure it was working, replaced everything, started it up, let it warm up, added about another half gallon, and life is good since. Oh yeah, not to overlook the obvious, ensure that the stat is stuffed spring side in manifold.
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