Engine Cylinder Head Temp a Little High
huntnCJfool
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- Meeker
- Vehicle(s)
- '79 CJ5, 258 I6, Weber 38 DGMS, T18 & Dana 20, AMC 20 Rear, Dana 30 Front, Rolling on 31x10.5x15's
I will try to keep this brief as I have not run all tests, but I am a bit perplexed at the moment. I finally had the opportunity to go on a longer test drive after swapping AMC 258 i6 / 4.2l 's and has some higher heat, but only at the cylinder head sensor port.
I have a 195 degree stat, and have two electronic sensors. One at the stock port in the head, the other is in the furthest rear block port. Now yesterday on my drive, the sensor from the head was going into the 200's on the guage, while the one in the block never got above 197. Before I did the engine swap, the same guage in the head never climbed much above 195 unless I was doing some climbing at highway speed in summer...
The t-stat is not that old, but reused from previous engine. I plan to pull it later today and see what temp it is opening but it seems to be opening and I can watch the temp drop when it does. Whether it is inconsistent I cannot say. The water pump is the same, less than 5 years old, bearing tight, I kept it. Basically I kept my entire old cooling system that worked and never overheated, and just swapped the engine which is why I am perplexed (radiator and cap are 2 years old also, heater core is 1 year old, hoses are a couple years old). I should not be having any of these reverse water pump issues people talk about because both 258s were v-belt setups. Coolant and oil are both still very clean so I cannot imagine it is a head gasket...but if it is I don't want to miss it. Would my temp just continue to climb if it was, because mine stabilized just runs hotter. Carbon buildup seems unlikely.
What could I be missing here before I drain coolant and start pulling parts and swapping sensors? I am not really concerned by any extra work even if it does ccome to needing to do the head gasket, because this engine sounds and runs great (besides the overheating!).
I am going to do the following today and will follow up with results
Get engine up to temp, check temps at various places throughout the cooling system
See if I can see coolant flowing when t-stat opens in radiator
Pull stat and test in water with a thermometer
I have a 195 degree stat, and have two electronic sensors. One at the stock port in the head, the other is in the furthest rear block port. Now yesterday on my drive, the sensor from the head was going into the 200's on the guage, while the one in the block never got above 197. Before I did the engine swap, the same guage in the head never climbed much above 195 unless I was doing some climbing at highway speed in summer...
The t-stat is not that old, but reused from previous engine. I plan to pull it later today and see what temp it is opening but it seems to be opening and I can watch the temp drop when it does. Whether it is inconsistent I cannot say. The water pump is the same, less than 5 years old, bearing tight, I kept it. Basically I kept my entire old cooling system that worked and never overheated, and just swapped the engine which is why I am perplexed (radiator and cap are 2 years old also, heater core is 1 year old, hoses are a couple years old). I should not be having any of these reverse water pump issues people talk about because both 258s were v-belt setups. Coolant and oil are both still very clean so I cannot imagine it is a head gasket...but if it is I don't want to miss it. Would my temp just continue to climb if it was, because mine stabilized just runs hotter. Carbon buildup seems unlikely.
What could I be missing here before I drain coolant and start pulling parts and swapping sensors? I am not really concerned by any extra work even if it does ccome to needing to do the head gasket, because this engine sounds and runs great (besides the overheating!).
I am going to do the following today and will follow up with results
Get engine up to temp, check temps at various places throughout the cooling system
See if I can see coolant flowing when t-stat opens in radiator
Pull stat and test in water with a thermometer