heat guage
budkat
03-29-2006, 10:28 PM
[email protected] my heat guage goes up on hot and within a few seconds comes back down to normal while driving.I have a complete new cooling system put in and a head gasket replaced what else could make the heat guage irratic?this is on a 92 voyager with a 2.5 please help me figure it out.
budkat:banghead:
budkat:banghead:
KManiac
03-30-2006, 12:00 AM
Oh wow, de-ja-vu (...a little French lingo there.). Here are excerps from my thread in the "Nonspecific" Dodge forum from about a month ago:
Post 1
"I have a 1991 Dodge Shadow ES convertible with 2.5 Turbo engine. I have recently encountered a strange problem with the cooling system. Or at least the symptom of my problem appears in the cooling system.
When ever I start the car cold after letting it sit more than 24 hours, I encounter the following scenario:
For the first three miles of driving, the temperature gauge will slowly climb from C to full H. Then it will quickly drop to the first hash mark at the low end of the driving range, then settle at the second hash mark, approximately 1/3 up the gauge from C.
When I have caught this at the right time, I discovered that the upper radiator hose was cold to the touch while the temperature gauge was hovering at H. When the gauge drops, the upper radiator hose is now warm, indicating that the thermostat is staying shut while it heats to H.
After it did this to me the first couple of times, I instinctively replaced the thermostat (thought it was bad) and flushed the cooling system. Now, with new thermostat and new coolant, it is doing it again. It won't do it if I drive the car daily, only when it sits over 24 hours. Since I flushed the cooling system, the water level in the overflow tank has dropped slightly, but there is no evidence of an external leak.
Has anyone else out there experienced anything like this before? I have heard of engines acting this way if you don't bleed the air out of the thermostat chamber after a flush. Could I somehow have an internal coolant leak causing an air bubble behind the thermostat after it sits for 24 hours?
Any thoughts on this would be greatly appreciated."
Post 2
"Here is an update as of today. I removed the thermostat, which is only two weeks old, and drilled a 3/32-inch weep hole in the body to allow for air release. I put it back together and took it for a drive. No overheating problem as of yet. But a few minutes after I parked it, I saw coolant dripping on the ground. I opened the hood and found a pinhole leak in the radiator, along the seal between the plastic side tank and the core. Now I know where the coolant has been disappearing. This morning, I popped off the radiator cap and started the engine cold. Coolant did not escape or even rise in level, so I think the head gasket is good for now.
Does anyone know if anybody makes an "all-metal" radiator for these cars? This is the second plastic radiator that has leaked on me like this since I bought the car 13 years ago."
Post 3
"I got a new radiator. Unfortunately, there are no "all-metal" replacements available. I replaced the radiator last weekend. So far, it has worked just fine. This time I found a fatigue crack in the metal along the metal edge that crimps around one of the plastic tanks. Looks like I'm good for another five years."
Since you have the same symptoms as I had, you most likely have a leak somewhere in the cooling system that allows air to accumulate behind the thermostat. You mention that you have a "complete new cooling system". Does this mean that you replaced everything cooling system related, including the radiator, water pump, thermostat, hoses, heater core and freeze plugs? If not, what on this list did you not replace. The leak may be with the cooling system components that were overlooked. Drilling a weep hole in the thermostat will remedy the situation for you. But I strongly suggest you look for possible leaks in the cooling system.
Please keep us posted with what you find and what you do.
Post 1
"I have a 1991 Dodge Shadow ES convertible with 2.5 Turbo engine. I have recently encountered a strange problem with the cooling system. Or at least the symptom of my problem appears in the cooling system.
When ever I start the car cold after letting it sit more than 24 hours, I encounter the following scenario:
For the first three miles of driving, the temperature gauge will slowly climb from C to full H. Then it will quickly drop to the first hash mark at the low end of the driving range, then settle at the second hash mark, approximately 1/3 up the gauge from C.
When I have caught this at the right time, I discovered that the upper radiator hose was cold to the touch while the temperature gauge was hovering at H. When the gauge drops, the upper radiator hose is now warm, indicating that the thermostat is staying shut while it heats to H.
After it did this to me the first couple of times, I instinctively replaced the thermostat (thought it was bad) and flushed the cooling system. Now, with new thermostat and new coolant, it is doing it again. It won't do it if I drive the car daily, only when it sits over 24 hours. Since I flushed the cooling system, the water level in the overflow tank has dropped slightly, but there is no evidence of an external leak.
Has anyone else out there experienced anything like this before? I have heard of engines acting this way if you don't bleed the air out of the thermostat chamber after a flush. Could I somehow have an internal coolant leak causing an air bubble behind the thermostat after it sits for 24 hours?
Any thoughts on this would be greatly appreciated."
Post 2
"Here is an update as of today. I removed the thermostat, which is only two weeks old, and drilled a 3/32-inch weep hole in the body to allow for air release. I put it back together and took it for a drive. No overheating problem as of yet. But a few minutes after I parked it, I saw coolant dripping on the ground. I opened the hood and found a pinhole leak in the radiator, along the seal between the plastic side tank and the core. Now I know where the coolant has been disappearing. This morning, I popped off the radiator cap and started the engine cold. Coolant did not escape or even rise in level, so I think the head gasket is good for now.
Does anyone know if anybody makes an "all-metal" radiator for these cars? This is the second plastic radiator that has leaked on me like this since I bought the car 13 years ago."
Post 3
"I got a new radiator. Unfortunately, there are no "all-metal" replacements available. I replaced the radiator last weekend. So far, it has worked just fine. This time I found a fatigue crack in the metal along the metal edge that crimps around one of the plastic tanks. Looks like I'm good for another five years."
Since you have the same symptoms as I had, you most likely have a leak somewhere in the cooling system that allows air to accumulate behind the thermostat. You mention that you have a "complete new cooling system". Does this mean that you replaced everything cooling system related, including the radiator, water pump, thermostat, hoses, heater core and freeze plugs? If not, what on this list did you not replace. The leak may be with the cooling system components that were overlooked. Drilling a weep hole in the thermostat will remedy the situation for you. But I strongly suggest you look for possible leaks in the cooling system.
Please keep us posted with what you find and what you do.
Stevo2
03-30-2006, 05:33 AM
How long ago was the thermostat replaced? I have seen some of the aftermarket cheap ones crap out in a month! Get one from the dealer.
budkat
03-30-2006, 08:35 PM
I have replaced the thermostat at the dealer one month a go we replaced the radiator had the system flushed the water pump is good all hoses replaced we even had a new head gasket put in.can air get trapped in the cooling system?
budkat
budkat
KManiac
03-30-2006, 10:32 PM
The only time air can get trapped in the cooling system is during the refilling process after a drain, or from leakage while the engine is NOT RUNNING. Any trapped air bubbles in the cooling system are expelled when the engine warms and the thermostat opens. Once the engine cools, the coolant shrinks and draws excess coolant back into the radiator from the overflow tank.
Given all that you have done, I think Stevo is right and you got a bum thermostat. Try replacing again with another one from the Dealer. It is more cost effective to do this yourself, if you can.
Let us know what you do and what happens.
Given all that you have done, I think Stevo is right and you got a bum thermostat. Try replacing again with another one from the Dealer. It is more cost effective to do this yourself, if you can.
Let us know what you do and what happens.
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