needing help with 4.0l
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needing help with 4.0l
let me bring you up to speed with me situation. i was having some overheating issues, so i replaced the temp probe, then the thermostat. after still having the same problem i replaced the water pump, went smoothly and got everything back together. me being dumb i forgot to put the drained coolant. long story short i blew the head gasket. after many hours and lots of curse words later i finally got the gasket changed and the engine put back together. everything ran good, until i noticed the fan was stuck on defroster, and wouldnt change. not a huge deal, i did notice my temp gauge bouncing around, so i attempted to bleed the system a few times. this last time i bled the system my heater went out and the temp gauge no longer bounces, it hits red and goes further. so my cooling system is not working, as well as my fan being stuck on defroster, from what i can gather there is no circulation of the coolant at all. from what the symptoms i think its either a bad stat, a bad pump, or no coolant. but all that was dealt with before with new parts. did i miss anything? im kinda on my wits end with this, considering my truck has only been driving less than 6 months this year.
Lead Driver
Joined: Sep 2003
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From: SoCal
When the head gaskets blow on these engines, it's usually because the heads got warped from overheating. Did you have the heads resurfaced before replacing the gaskets? If not, they'll just continue to leak.
The air always going to the defroster means there is no vacuum actuating the doors that redirect the air flow to other vents. Look for a disconnected or broken vacuum line.
You can check the thermostat by putting it in a pot of water and heating it on your stove. You should see it open at some point, and you can use a cooking thermometer to measure that temperature.
When my engine was low on coolant, I first saw no activity on the temp gauge, and air coming out of the heater was stone cold. Then I watched the temp gauge rise very quickly, going into the red zone, and then finally settling down into the normal range, and the air coming out heated up. Some of your symptoms seem to point to this.
None of these checks will mean much if your heads are still leaking from being warped.
The air always going to the defroster means there is no vacuum actuating the doors that redirect the air flow to other vents. Look for a disconnected or broken vacuum line.
You can check the thermostat by putting it in a pot of water and heating it on your stove. You should see it open at some point, and you can use a cooking thermometer to measure that temperature.
When my engine was low on coolant, I first saw no activity on the temp gauge, and air coming out of the heater was stone cold. Then I watched the temp gauge rise very quickly, going into the red zone, and then finally settling down into the normal range, and the air coming out heated up. Some of your symptoms seem to point to this.
None of these checks will mean much if your heads are still leaking from being warped.
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Freshman User
Joined: Jan 2016
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When the head gaskets blow on these engines, it's usually because the heads got warped from overheating. Did you have the heads resurfaced before replacing the gaskets? If not, they'll just continue to leak.
The air always going to the defroster means there is no vacuum actuating the doors that redirect the air flow to other vents. Look for a disconnected or broken vacuum line.
You can check the thermostat by putting it in a pot of water and heating it on your stove. You should see it open at some point, and you can use a cooking thermometer to measure that temperature.
When my engine was low on coolant, I first saw no activity on the temp gauge, and air coming out of the heater was stone cold. Then I watched the temp gauge rise very quickly, going into the red zone, and then finally settling down into the normal range, and the air coming out heated up. Some of your symptoms seem to point to this.
None of these checks will mean much if your heads are still leaking from being warped.
The air always going to the defroster means there is no vacuum actuating the doors that redirect the air flow to other vents. Look for a disconnected or broken vacuum line.
You can check the thermostat by putting it in a pot of water and heating it on your stove. You should see it open at some point, and you can use a cooking thermometer to measure that temperature.
When my engine was low on coolant, I first saw no activity on the temp gauge, and air coming out of the heater was stone cold. Then I watched the temp gauge rise very quickly, going into the red zone, and then finally settling down into the normal range, and the air coming out heated up. Some of your symptoms seem to point to this.
None of these checks will mean much if your heads are still leaking from being warped.
Lead Driver
Joined: Sep 2003
Posts: 7,018
Likes: 210
From: SoCal
Well, you didn't mention coolant in the oil before. Indeed, the most likely source is in the lower intake manifold gaskets. You might want to be certain by pressure testing the cooling system. You can get one of those pumps that installs in place of the radiator cap and pump it up. I made my own with a T-fitting plumbed into a heater hose (made for flushing the cooling system) and adapted a cap with a presta air valve from a bicycle inner tube. I pump it up with a bike pump, and I can test the radiator cap release pressure at the same time.
A leak in the head gasket usually results in combustion gasses in the coolant that you can smell and see. It also pushes the coolant into the overflow tank.
A leak in the head gasket usually results in combustion gasses in the coolant that you can smell and see. It also pushes the coolant into the overflow tank.
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Well, you didn't mention coolant in the oil before. Indeed, the most likely source is in the lower intake manifold gaskets. You might want to be certain by pressure testing the cooling system. You can get one of those pumps that installs in place of the radiator cap and pump it up. I made my own with a T-fitting plumbed into a heater hose (made for flushing the cooling system) and adapted a cap with a presta air valve from a bicycle inner tube. I pump it up with a bike pump, and I can test the radiator cap release pressure at the same time.
A leak in the head gasket usually results in combustion gasses in the coolant that you can smell and see. It also pushes the coolant into the overflow tank.
A leak in the head gasket usually results in combustion gasses in the coolant that you can smell and see. It also pushes the coolant into the overflow tank.
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big update, drained my oil and no coolant what-so-ever, flushed both the cooling system and the oil system. everything seams to be ok, ill be checking my fluids religiously for a while to make sure everything stays where it should.
Lead Driver
Joined: Sep 2003
Posts: 7,018
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From: SoCal
That seems to be a major part of maintenance; keeping fluids in where they belong and out of where they don't. Hope you're all set now.
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thanks, im glad for now things are ok, it seams to have been a lapse in judgment on my part for this problem. well at least i did learn that it takes a bit for the coolant to settle in the radiator properly.
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