I have a 97 D1 with about 196K miles. The vehicle is in excellent condition.
Problem:
In the warm weather with the A/C on, the temp. gauge seems to rise when the car is in traffic, etc. I never let the needle get too high because when it begins to rise it continues to do so. I would say the needle is typically at the 40-45% position (below middle). When the temp begins to rise I let it get to the 60-65% position (above middle) and then turn off the A/C.
Background:
I have had it at the dealer for diagnoses over the past year to year or so with no true answer (at that time the car had about 140K miles). I even had the head mechanic look into this issue. The following items/parts have been repaired/replaced (mostly replaced):
1) Radiator (around 110K) and water pump -- installed in the cooler weather months
2) Thermostat (a few of them since the beginning of this problem)
3) Temp Sending Unit
4) Heater Core
5) Viscous clutch fan (twice since problem first reported)
6) Hoses
7) Coolant resevoir tank (very recently since the original one completely rupture; my guess is probably because of the overheating issue and I forget to check the temp needle)
8) Intake manifold gasket
9) Retest the coolant's specific gravity
10) Other items for which I do not remember. One of these was cleaning the leaves in front of the radiator.
On cooler mornings, especially winter, I often hear the sound of fluid rush into the dashboard. This is usually a sign of low coolant, a bad heater core, and/or a leak. Since the heater core was replaced (a few months ago), the problem still persists. The system was pressure tested (on a few occasions) but no leak was ever found.
My Theories/Questions:
1) I never liked the coolant rush sound and feel this may be at the heart of the problem. Perhaps there is a leak in the system that gets sealed when the engine warms up and expands rubber, etc. Before it seals it permits air into the system possibly causing a bubble and disrupting coolant flow. A problem like this is difficult for a dealer to diagnose because they basically run the car for 20-30 minutes and then check things.
2) The replacement radiator not sufficient to cool engine coolant. I replaced the radiator in the late fall/early winter months a coupld of years ago with a factory replacement part from the dealer. The problem did not surface after installation because it was cold weather. But, as the warm weather arrived, some 30K miles later (I drive a lot), this issue began. Coincidence?
3) Perhaps my engine block's coolant passageways have become clogged a bit, not allowing enough flow to properly cool the engine.
4) My A/C compressor may require too much effort to turn (it is original) and thus loads engine too heavily.
5) Sometimes when the car is turned off, the electric fans keep running for a few minutes. I cannot tell when these fans will stay on and when they won't. One time recently, when I turned off the car, the coolant temp on the gauge was elevated and I figured that the fans would come on and stay on after I turned off the ignition; but they did not. Other times, the temp is perfectly fine but the fans run.
6) There are no visible leaks or smells of coolant.
Does anyone have an answer to this perplexing and troubling problem?
Thanks
Problem:
In the warm weather with the A/C on, the temp. gauge seems to rise when the car is in traffic, etc. I never let the needle get too high because when it begins to rise it continues to do so. I would say the needle is typically at the 40-45% position (below middle). When the temp begins to rise I let it get to the 60-65% position (above middle) and then turn off the A/C.
Background:
I have had it at the dealer for diagnoses over the past year to year or so with no true answer (at that time the car had about 140K miles). I even had the head mechanic look into this issue. The following items/parts have been repaired/replaced (mostly replaced):
1) Radiator (around 110K) and water pump -- installed in the cooler weather months
2) Thermostat (a few of them since the beginning of this problem)
3) Temp Sending Unit
4) Heater Core
5) Viscous clutch fan (twice since problem first reported)
6) Hoses
7) Coolant resevoir tank (very recently since the original one completely rupture; my guess is probably because of the overheating issue and I forget to check the temp needle)
8) Intake manifold gasket
9) Retest the coolant's specific gravity
10) Other items for which I do not remember. One of these was cleaning the leaves in front of the radiator.
On cooler mornings, especially winter, I often hear the sound of fluid rush into the dashboard. This is usually a sign of low coolant, a bad heater core, and/or a leak. Since the heater core was replaced (a few months ago), the problem still persists. The system was pressure tested (on a few occasions) but no leak was ever found.
My Theories/Questions:
1) I never liked the coolant rush sound and feel this may be at the heart of the problem. Perhaps there is a leak in the system that gets sealed when the engine warms up and expands rubber, etc. Before it seals it permits air into the system possibly causing a bubble and disrupting coolant flow. A problem like this is difficult for a dealer to diagnose because they basically run the car for 20-30 minutes and then check things.
2) The replacement radiator not sufficient to cool engine coolant. I replaced the radiator in the late fall/early winter months a coupld of years ago with a factory replacement part from the dealer. The problem did not surface after installation because it was cold weather. But, as the warm weather arrived, some 30K miles later (I drive a lot), this issue began. Coincidence?
3) Perhaps my engine block's coolant passageways have become clogged a bit, not allowing enough flow to properly cool the engine.
4) My A/C compressor may require too much effort to turn (it is original) and thus loads engine too heavily.
5) Sometimes when the car is turned off, the electric fans keep running for a few minutes. I cannot tell when these fans will stay on and when they won't. One time recently, when I turned off the car, the coolant temp on the gauge was elevated and I figured that the fans would come on and stay on after I turned off the ignition; but they did not. Other times, the temp is perfectly fine but the fans run.
6) There are no visible leaks or smells of coolant.
Does anyone have an answer to this perplexing and troubling problem?
Thanks
