Overheating issue

Joe1234 · 11-13-2014, 03:25 AM

Hey guys. I need a little help and need some opinions before I start ripping this 7mgte apart. The engine Is having an overheating issue and I have no idea whats causing it. The engine only overheats when I use boost, and I'm not talking about flooring it, im just talking about maybe using 1 or 2 pounds of boost, but if I drive under 2500rpm it doesn't overheat. I'm assuming maybe the head gasket could be leaking but not exactly cracked yet? Maybe it's loose and I just need to tighten it? I wana make sure before I start digging in there. Thanks guys

Bru · 11-13-2014, 06:29 PM

Replace the thermostat and radiator cap if they are old. You can check a thermostat by taking it out and heating to near boiling in water. If it opens its good. Check the viscous fan clutch by pushing on a fan blade with a forceful 5 inch push. It should not rotate more than about 1/4 of a turn. Take a peek at the front of the radiator for leaves, dirt, feathers, ect. You can clean it on the car by carefully spraying with a garden hose from the fan side (not too much pressure the fins bend easily). If the fins are rotten (crumble to dust) replace the radiator. Take a look into the radiator under the cap at the cores. If they look plugged up, take the radiator off the car and back flush it with a garden hose. Clean the fins while you are at it.
Make sure the coolant level in the radiator is full and the overflow hose is working. I had one plug up on me. With the engine cold, put a paper towel under the hose where it meets the radiator and pull it off. Gently blow into the hose, it should bubble in the overflow tank. Clear any obstruction if it doesn't. Keep the overflow coolant level between the lines. I use a flashlight on top of the tank and shake the tank a little. Make sure the fan belt is properly adjusted.

Joe1234 · 11-13-2014, 07:13 PM

I have flushed the radiator and the flow is great. I have done an experiment where I drive around using the turbo and not using the turbo at all. When using the turbo it appears that coolant seems to be missing but when I avoid the use of the turbo as much as possible, no coolant is missing.

Bru · 11-13-2014, 09:25 PM

When its a blown head gasket (or a cracked head) to the cooling system the symptoms are that after driving and shutting down the engine you hear a lot of sounds from the radiator cap and the over flow tank fills up and overflows onto the ground. Do you see a puff of white smoke on first start up in the morning? White smoke is usually coolant. Grey blue smoke is oil.

Joe1234 · 11-13-2014, 10:35 PM

I do see white smoke but I assume it's condensation because it's cold outside now . . After the car warms up after 10 min the white smoke goes away. There's no sounds from the radiator cap but some coolant flows to the overflow tank and its boiling after I shut the car off. But that's when the car is pretty much overheating .

Bru · 11-14-2014, 01:28 AM

When I had a cracked head 2 years ago the symptoms were a puff of white smoke on start up that would go away. As it got worse I had overheating problems. There are several tests for exhaust gasses in the coolant from cracked heads or gaskets. Check out youtube for this subject. I would still check or change the thermostat. If it does not open the engine will overheat.

Joe1234 · 11-14-2014, 03:04 AM

Okay I will try. Thank u so much for your help . I'm really hoping the head gasket isn't cracked or leaking, I'd be devastated��

11-13-2014, 03:25 AM	#1
Joe1234 Stock Join Date: Nov 2014 Location: Bayside Posts: 8	Overheating issue Hey guys. I need a little help and need some opinions before I start ripping this 7mgte apart. The engine Is having an overheating issue and I have no idea whats causing it. The engine only overheats when I use boost, and I'm not talking about flooring it, im just talking about maybe using 1 or 2 pounds of boost, but if I drive under 2500rpm it doesn't overheat. I'm assuming maybe the head gasket could be leaking but not exactly cracked yet? Maybe it's loose and I just need to tighten it? I wana make sure before I start digging in there. Thanks guys

11-13-2014, 06:29 PM	#2
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	Replace the thermostat and radiator cap if they are old. You can check a thermostat by taking it out and heating to near boiling in water. If it opens its good. Check the viscous fan clutch by pushing on a fan blade with a forceful 5 inch push. It should not rotate more than about 1/4 of a turn. Take a peek at the front of the radiator for leaves, dirt, feathers, ect. You can clean it on the car by carefully spraying with a garden hose from the fan side (not too much pressure the fins bend easily). If the fins are rotten (crumble to dust) replace the radiator. Take a look into the radiator under the cap at the cores. If they look plugged up, take the radiator off the car and back flush it with a garden hose. Clean the fins while you are at it. Make sure the coolant level in the radiator is full and the overflow hose is working. I had one plug up on me. With the engine cold, put a paper towel under the hose where it meets the radiator and pull it off. Gently blow into the hose, it should bubble in the overflow tank. Clear any obstruction if it doesn't. Keep the overflow coolant level between the lines. I use a flashlight on top of the tank and shake the tank a little. Make sure the fan belt is properly adjusted. Last edited by Bru; 11-13-2014 at 06:32 PM.

11-14-2014, 03:04 AM	#7
Joe1234 Stock Join Date: Nov 2014 Location: Bayside Posts: 8	Okay I will try. Thank u so much for your help . I'm really hoping the head gasket isn't cracked or leaking, I'd be devastated�� Last edited by Joe1234; 11-14-2014 at 03:06 AM.

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11-13-2014, 07:13 PM	#3
Joe1234 Stock Join Date: Nov 2014 Location: Bayside Posts: 8	I have flushed the radiator and the flow is great. I have done an experiment where I drive around using the turbo and not using the turbo at all. When using the turbo it appears that coolant seems to be missing but when I avoid the use of the turbo as much as possible, no coolant is missing.

11-13-2014, 09:25 PM	#4
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	When its a blown head gasket (or a cracked head) to the cooling system the symptoms are that after driving and shutting down the engine you hear a lot of sounds from the radiator cap and the over flow tank fills up and overflows onto the ground. Do you see a puff of white smoke on first start up in the morning? White smoke is usually coolant. Grey blue smoke is oil.

11-13-2014, 10:35 PM	#5
Joe1234 Stock Join Date: Nov 2014 Location: Bayside Posts: 8	I do see white smoke but I assume it's condensation because it's cold outside now . . After the car warms up after 10 min the white smoke goes away. There's no sounds from the radiator cap but some coolant flows to the overflow tank and its boiling after I shut the car off. But that's when the car is pretty much overheating .

11-14-2014, 01:28 AM	#6
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	When I had a cracked head 2 years ago the symptoms were a puff of white smoke on start up that would go away. As it got worse I had overheating problems. There are several tests for exhaust gasses in the coolant from cracked heads or gaskets. Check out youtube for this subject. I would still check or change the thermostat. If it does not open the engine will overheat.