Car overheats after driving on freeway for about a hour.
 

My 87 turbo overheats when i drive on the freeway for about an hour. it seems like coolent is coming out the overflow and all over the intercooler. I drove it back to my mechanic and he said the radiator was leaking. so he replaced the rad and the thermostat. i told him i think it might be the head gasket. he said that it shouldnt be because there should be tons of white smoke coming out the exhaust. so i let him be since hes the expert and im not. i took it back on the freeway... and sure enough after about an hour... the temp started climbing up again. up to max. so i pulled into a gas station. carefully removed the rad cap and added 2 litres of coolent. i lost a bunch out of the overflow again... it was all over the intercooler. after adding the coolent. it was back down to normal temp again. I drove it back to him and said it overheated again. i said i really think its a bhg. he said he'd take a closer look. the next day i called him up and he said he fixed the problem. i asked him wat was wrong. he said a bunch of things i could barely understand him because the phones were fuzzy. but he said that he ran it for over 3 hours and it was fine so it is all good. i am not sure if he actually drove it at freeway speeds though. i have a feeling that he just idled it for 3 hours. what do you think i should do because i need to drive it 4 hours.. cuz i live 400km or 250 miles away. i was thinking about just giving it a shot and try to take the car home.. if it overheated again i'd pull into a gas station.. let it cooldown a bit and add more coolant. the problem seems to be losing coolant. the oil isnt milky and there doesnt seem to be oil in the coolant. i dont wanna tow it cuz i dont have that kinda money. any suggestions? And sorry for the long ass write up.
The car drives around town just fine. just overheats at freeway speeds.

Well first and most easy is to check and replace the thermostat :P. But other than that I would assume it to be a blown head gasket.

I've had the same thing happen to me before and I just couldn't figure it out. But after a compression test I found out my cylinders were all messed up = bhg.

Got a new radiator and thermostat. I asking would it be ok to just drive it about an hour.. till it starts to heat up.. pull over add more coolant.. and let the car cool down.. then drive it for about another hour? and so on? i need to get the car home which is 400 km or 250 miles away. which is about a 4 hour drive. non-stop. anyone got suggestions?

If you've got an blown head gasket then no it's not okay because you might end up stranded in the middle of nowhere. If you are having overheating problems I suggest that you don't drive it long distances especially 4 hours away. I'd be best to get the problem fixed first. Drive a different car if possible. You might end up having to chuck up more money in the end by warping your head and block due to constant overheating and cooling.

so i drove home today. i set the cruise control at 100 km/h or 60mph. the temp needle didnt budge. until there was stop and go traffic it started to rise. but then i got past the trafic and got back up to speed and the temp went down again. the needle started to rise again so i pulled into a gas station. i carefully opened up the radiator and added almost 2 litres of coolant. i let the rest cool down. then i drive another 200kms without a problem at all. i had to piss reeaall bad ahah so i pulled into a town.. as soon as i slowed down to 50-60 km/h (abour 30-35mph) the temp started to rise again. i could have made it all the way home. anyway... i did the same thing again. added tons of coolant. looks like the coolant was coming out of the overflow. do you guys think is a blown headgasket?

Yep. What you're describing with the coolant and overflow tank is an archtypical sign of a blown head gasket. Get a block test and run it, or a compression test if you prefer.

Need to ask though, are you confident of your fan clutch? If it's bad it could explain the overheating at low speeds, though I think it may be too late for the hg even if that is what was going on.

Given the age of the car and that you've been driving it around while it was overheating, if the test is positive for a bhg I'd go ahead and look around for a reputable shop/machinist as your head and/or block may well need resurfacing before putting a new hg on.

I had this and mine was an air lock in the heater matrix, on a 5 mile run it would blow a lot of water out of the overflow I've cured it by making a bleed valve and fitting it in the top heater hose. I used standard 15mm plumbing fittings and a house radiator bleed valve. Fill the rad as normal and then refit the cap( I replaced mine because it let water out without being under pressure ) take out the bleed valve from its seat and you can get another 1/2 pint of water into the system through that hole. Put the bleed nipple back, run it till it's hot, and bleed it as if it was a house radiator. My mate had the same problem and has cured his the same way. If I can work out how to add pictures to this I'll post them

Hi,

I am having the same problem. I have 1999 toyota camry. My car runs OK at city limit speeds and on freeways. But once it comes out of freeway it starts overheating. I took it to a autoshop and they first replaced water pump and timing belt. Thereafter they replaced radiator. I also suspect that it is losing coolant too because last time i have to fill coolant after about a 1000 miles while I normally used to do it after 3000 miles (regular maintenance). However when I took it back to the autoshop they could not find anything wrong. They told me that they kept the car running for about 4 hrs and the engine never overheated. I believe that they have tested it by keeping my car running for that long as my gas tank was lower by about 3-4 gallons. What do you think guys. Problem looks similar to your problem. How did you fixed it? Any suggestion are greatly appriciated.

Just to chime in something here, but I am certainly no expert, but I've read here that systems should not lose coolant Period. If the levels need to be replaced like in a year or two at all, then you have either a leak or a BHG aka the blown head gasket. I don't know your car, but I doubt it's a BHG. That's special to us Supra owners due to a factory error. But I'd bet you have a coolant leak somewhere. If there is no leak at all and you are sure of it, check your oil for milkiness in it, not pure oil, and look for smoke in your exhaust - the symptoms of BHG.
I'd run it and take it home and put some white cloth or cardboard underneath it overnight and see if there are any stains or fluid on it at all the next day. You might have a small lose fitting on a coolant hose somewhere, that only starts leaking and spraying when the motor is warm, the thermo is open, and the temp and pressure is way up to force it out.
That's essentially what happened to me, at least I think so. I'd lose tons of coolant after full temp and running the motor at over 2000 rpm on highway, then the coolant would let loose everywhere and I'd overheat. I replaced the water pump, the thermostat (was coming out around that area) but did not fix it. I have a small very difficult to see small coolant hose that I am replacing tomorrow and another one that I know isn't leaking to be safe, and the gasket to the water outlet housing (where the thermo bolts into which bolts into the head). I have a full long saga posted here if you want to read more.
Good luck