Coolant temperature VERY hot while towing-Problem found!!
EDIT: Problem found, see post#33
Warning: long post with lots of details to help you diagnose.
1994, about 150,000 miles, stock gears, 285/75 tires, towing around 4000-4300 lbs. with some long uphills up to 6000 ft. New two row Spectra Premium aluminum radiator, hoses, and thermostat less then a year ago, Aisin blue fan clutch just drained and refilled with 10k cst a month ago. Radiator cap is a Stant in good shape, releases at 13 psi like it should, only holds 10 psi long term on the tester, but allows coolant to go both ways like it should. Cooling system holds 14 psi fine. Cooling temperature gauge installed with sender in the outlet of the head on the drivers side where everyone installs them, which is about the hottest place. Snorkel installed for cooler intake air temps. 50/50 mix of green. Driving around town normally I get 180-195 temps. Got 10.2 mpg while towing on this trip.
On my last trip I towed my travel trailer about 400 miles each way. On the way there outside temps were around 80, and I got the cooling system up to 228 at one point briefly. That was in second gear, 4000-4400 rpm up a steep hill for an extended period. Transmission got up to 200. It would cool off relatively quickly and quite a bit on the downhills. I was normally running around 200-215 on flat ground with the AC on a lot. I ran both heaters on high on the steep hills.
On my way back, outside temp was 95, cooling system got up to a max of 235 once, and a number of times was 220-230, again up the same steep hills, second gear, 4000-4400 rpm for an extended period. Transmission got up to 219. It did not seem to cool of as much or near as quickly going on the down hills. On flat ground I was running around 208-224. I ran both heaters on high on the steep hills, and even on the relatively flat ground near the end of the trip.
Besides it getting really hot, here is the weird thing. Ever since I bought it 4 years ago, it has always seemed to overfill and spill out coolant from the overflow bottle on long trips. This last trip, radiator was full, overflow had a little in it, and within an hour of towing which included one steep, long hill, the overflow was completely full and it had been spewing some out of the overflow bottle. On the way back I actually had the radiator down about an inch with the overflow empty, and the same thing happened: filled the bottle and spilled out more. The system seems to be over pressurizing. It even did this some when the radiator cap was new.
I have done two block tests, including one today, and fluid never changes color. Did the test with a cold engine, and at 190, both at idle and at 2000 rpm. So head gasket does not seem likely.
When engine is hot, the fan clutch can not be stopped by hand since I put the new fluid in.
The AC cut off is 226, with cut back in at 217. While at those extreme temps mentioned above, the engine was still pulling fine with seemingly no reduction in power. So my questions are:
1. Being that my gauge sender is in the hottest place, how hot is too hot?
2. Why is the system seemingly over pressurizing?
3. What can I do to bring these temps down some? I would like to keep it under 220 even on the steep hills while towing.
4. How long should a radiator cap last?
Thanks in advance for any help. I have searched and searched.
No offense, but please only reply if you really know what you are talking about, preferably with firsthand experience in a similar case if possible. I know what I am doing, but this one has me scratching my head...... About the only thing I can think of that I have not checked yet is if there are any cool spots in the new radiator pointing to a blockage, and I have not flushed out the system either.
For those of you that know southern California, the hills that gave me trouble were "Goat Mountain pass" halfway between Barstow and Lucerne Valley on route 247, Tehachipi hills on route 58, especially coming from the Bakersfield side, the long uphills going up to Yosemite on route 41 from Fresno, and going up to Big Bear from Lucerne Valley up the super steep and switchback route 18 (I actually go up this in low range from the cement plant to the top).
EDIT: Problem found, see post#33
Warning: long post with lots of details to help you diagnose.
1994, about 150,000 miles, stock gears, 285/75 tires, towing around 4000-4300 lbs. with some long uphills up to 6000 ft. New two row Spectra Premium aluminum radiator, hoses, and thermostat less then a year ago, Aisin blue fan clutch just drained and refilled with 10k cst a month ago. Radiator cap is a Stant in good shape, releases at 13 psi like it should, only holds 10 psi long term on the tester, but allows coolant to go both ways like it should. Cooling system holds 14 psi fine. Cooling temperature gauge installed with sender in the outlet of the head on the drivers side where everyone installs them, which is about the hottest place. Snorkel installed for cooler intake air temps. 50/50 mix of green. Driving around town normally I get 180-195 temps. Got 10.2 mpg while towing on this trip.
On my last trip I towed my travel trailer about 400 miles each way. On the way there outside temps were around 80, and I got the cooling system up to 228 at one point briefly. That was in second gear, 4000-4400 rpm up a steep hill for an extended period. Transmission got up to 200. It would cool off relatively quickly and quite a bit on the downhills. I was normally running around 200-215 on flat ground with the AC on a lot. I ran both heaters on high on the steep hills.
On my way back, outside temp was 95, cooling system got up to a max of 235 once, and a number of times was 220-230, again up the same steep hills, second gear, 4000-4400 rpm for an extended period. Transmission got up to 219. It did not seem to cool of as much or near as quickly going on the down hills. On flat ground I was running around 208-224. I ran both heaters on high on the steep hills, and even on the relatively flat ground near the end of the trip.
Besides it getting really hot, here is the weird thing. Ever since I bought it 4 years ago, it has always seemed to overfill and spill out coolant from the overflow bottle on long trips. This last trip, radiator was full, overflow had a little in it, and within an hour of towing which included one steep, long hill, the overflow was completely full and it had been spewing some out of the overflow bottle. On the way back I actually had the radiator down about an inch with the overflow empty, and the same thing happened: filled the bottle and spilled out more. The system seems to be over pressurizing. It even did this some when the radiator cap was new.
I have done two block tests, including one today, and fluid never changes color. Did the test with a cold engine, and at 190, both at idle and at 2000 rpm. So head gasket does not seem likely.
When engine is hot, the fan clutch can not be stopped by hand since I put the new fluid in.
The AC cut off is 226, with cut back in at 217. While at those extreme temps mentioned above, the engine was still pulling fine with seemingly no reduction in power. So my questions are:
1. Being that my gauge sender is in the hottest place, how hot is too hot?
2. Why is the system seemingly over pressurizing?
3. What can I do to bring these temps down some? I would like to keep it under 220 even on the steep hills while towing.
4. How long should a radiator cap last?
Thanks in advance for any help. I have searched and searched.
No offense, but please only reply if you really know what you are talking about, preferably with firsthand experience in a similar case if possible. I know what I am doing, but this one has me scratching my head...... About the only thing I can think of that I have not checked yet is if there are any cool spots in the new radiator pointing to a blockage, and I have not flushed out the system either.For those of you that know southern California, the hills that gave me trouble were "Goat Mountain pass" halfway between Barstow and Lucerne Valley on route 247, Tehachipi hills on route 58, especially coming from the Bakersfield side, the long uphills going up to Yosemite on route 41 from Fresno, and going up to Big Bear from Lucerne Valley up the super steep and switchback route 18 (I actually go up this in low range from the cement plant to the top).
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