Need help keeping car cool!!
#1
07-09-2009, 09:24 PM
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Need help keeping car cool!!
Hello all;
Radiator has been rodded, thermostat changed, temperature sender unit replaced, system flushed..Yet the temperature gauge goes above the "N" after about ten minutes of driving and if the car is pushed it goes dangerously close to the "H".Compression test OK..no coolant on my oil..fan working perfectly fine.. My oil pressure gauge and speedometer seemed to be getting a ground signal with the needles all the way on the opposite end of those respective gauges-the oil pressure gauge and sender where replaced and that now works OK and the speedometer problem went away on its own...At this point what is keeping my car in the shop is the overheating, a stuck fuel filter,no instrument cluster lights and a mildly rough idle. I have owned the car for two months and have driven it about two days in between the body shop and my mechanic. If at least the overheating can be solved I could drive this thing. I am so tired of going to the mechanics and just staring at my car and keeping my fingers crossed that the next thing we try will work....not to mention my poor pathetic wallet.
ANY IDEAS ON HOW TO KEEP THIS THING COOL?
Your help on getting my car on the road is GREATLY APPRECIATED!!
Radiator has been rodded, thermostat changed, temperature sender unit replaced, system flushed..Yet the temperature gauge goes above the "N" after about ten minutes of driving and if the car is pushed it goes dangerously close to the "H".Compression test OK..no coolant on my oil..fan working perfectly fine.. My oil pressure gauge and speedometer seemed to be getting a ground signal with the needles all the way on the opposite end of those respective gauges-the oil pressure gauge and sender where replaced and that now works OK and the speedometer problem went away on its own...At this point what is keeping my car in the shop is the overheating, a stuck fuel filter,no instrument cluster lights and a mildly rough idle. I have owned the car for two months and have driven it about two days in between the body shop and my mechanic. If at least the overheating can be solved I could drive this thing. I am so tired of going to the mechanics and just staring at my car and keeping my fingers crossed that the next thing we try will work....not to mention my poor pathetic wallet.
ANY IDEAS ON HOW TO KEEP THIS THING COOL?
Your help on getting my car on the road is GREATLY APPRECIATED!!
#2
07-10-2009, 11:23 AM
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Spike, what year vehicle are we looking at here? What I would recommend doing is essentially a calibration of the temperature sending unit. All this involves is attaching various size resistors in place of your temp sending unit. For example, most procedures have you use 3 resistors (20 ohm, 140 ohm, and 260 ohm; C, N, and H respectively). It is possible that your car is running at a normal temp but with the receiving unit not functioning properly, it can cause it to indicate wrong.
After that, how is your water pump doing? To me, it is sounding like it is starting to go. What you are experiencing is that under light loads, there is enough flow to maintain the motor at its proper temp, but the thermostat is open more than it needs to be. But, when you push the car, the water pump can't generate enough flow, resulting in your over heating condition. I have seen with other vehicles that with time, the blades of the water pump will wear, resulting in the water pump not being able to push fluid like it needs to.
Hope this helps.
After that, how is your water pump doing? To me, it is sounding like it is starting to go. What you are experiencing is that under light loads, there is enough flow to maintain the motor at its proper temp, but the thermostat is open more than it needs to be. But, when you push the car, the water pump can't generate enough flow, resulting in your over heating condition. I have seen with other vehicles that with time, the blades of the water pump will wear, resulting in the water pump not being able to push fluid like it needs to.
Hope this helps.
#3
07-10-2009, 10:29 PM
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Thanks for your help, Thermo. Today we found that the car is not overheating at all. This is what we found: we tried the thermometer and it shows at about 186 while my gauge reflects way pass the "N". Just to make sure we tried a mechanical thermometer and plugged it in on the site of the sender and it shows below 190 after 10 minutes of running. So we don't really have overheating...We next tried swaping gauges and printed circuit boards from another car with proper readings..gauge still showed incorrect reading.
Although I am very happy that I am not overheating, I do not where to go next to solve the problem.
Your input is greatly valued!!!
Thanks all!!
Although I am very happy that I am not overheating, I do not where to go next to solve the problem.
Your input is greatly valued!!!
Thanks all!!
#4
07-11-2009, 06:46 AM
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Spike, what year vehicle do you have? Depending on the year, I may have the diagrams for your vehicle and can then give you step by step instructions on what to check and isolate the problem down to a single component. But, many different systems have been used over the years. So, I need a little bit of information before I can be any more specific. I should be able to give you wire colors and expected voltages.
#6
08-21-2009, 05:46 PM
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Over heating
I have a similar problem and I didn't want to start a new thread. My XJS is a 1988 coupe.
My temp marker is going 1/2 way between N and H.
My mechanic has done most everything he can think of with little changing. Today I topped up the radiator and headed out for a drive. I noticed that I was spewing some fluid out. After about 20 minutes my temp dropped to normal.
When I got home, I noticed that I had a small steam emission from the small (bleeder?) hose right at the filler cap. I have also noticed that I have a 16# radiator cap there instead of the recommended 20#.
Could/would either of these things cause overheating?
They certainly spew fluids, 1 1/2 gallon after a 15 mile jaunt.
My temp marker is going 1/2 way between N and H.
My mechanic has done most everything he can think of with little changing. Today I topped up the radiator and headed out for a drive. I noticed that I was spewing some fluid out. After about 20 minutes my temp dropped to normal.
When I got home, I noticed that I had a small steam emission from the small (bleeder?) hose right at the filler cap. I have also noticed that I have a 16# radiator cap there instead of the recommended 20#.
Could/would either of these things cause overheating?
They certainly spew fluids, 1 1/2 gallon after a 15 mile jaunt.
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