Running out of options so ill start from the beginning. (all within the last month) Truck has new head gasket and Weber 38 carb. The carb could use a fine tuning but runs good not rough or boggy. I have replaced the water pump and alternator and radiator. few new rubber lines here and there. I have no heat in cab so i decided to flush the heater core, first i flushed it one way and it came out through the top of the radiator. A few days later i sprung a leak in the hose under the intake so i drained it all again and re-flushed it with a water hose from both sides of heater core hoses (this time not through rad) I then replaced that hose and made sure the 2 metal lines near it were not clogged. I keep blowing thermostats and it overheats. Ive gone through like 4 of them. I finally got a failsafe thermo and its just blown open right now so i don't have to worry atleast about overheating it. I don't know what else to do, however i do have high oil pressure on stock gauge. Couldn't tell you PSI but it sits 3/4 to all the way when heated up. used to sit 1/2 to 3/4 before Weber Carb. could the oil pump be bad/ fliter clogged in oil pan causing it to overheat? I did try blue devil sealer before changing head gasket and it didnt work, but i replaced the coolant and oil each like 4 times since new headgasket to get all that water and coolant out of my oil, and all other parts were replaced after like rad, water pump ect..I run 10w 30 full synthetic with zero leaks, Stock 4.37 gears and 32 12.50 tires on a 5'' suspension lift really nothing crazy. I'm so lost here and any suggestions are greatly appreciated.

 

The blue devil sealant is a radiator additive? If do that could be part of the problem. Did you flush the head and or block when you did the head gasket? Sometimes products like bars leak will plug cooling ports and prevent or greatly restrict water flow in areas? Have you confirmed the water pump is working? Start it cold with the cap off and wait for the thermostat to open. You should be able to see the coolant start to move. You said you flushed the heater core because you had no heat. Did this solve lack of heat problem. So you have heat now? If not I would look at the water pump or a plugged cooling passage/line.
Just some suggestions and questions off the top of my head.
Hope this helps. Keep us updated.

 

sounds like you plugged something up. did you tune that weber properly?

 

The blue devil is a coolant sealer. Yeah i flushed it out many times after and got it all out, cant see flakes anywhere anymore. Today I realized i didnt flush the block out, so gunk came out of that screw under the manifold. Weber is definitely tuned correctly and i did some wheeling today to make sure it didn't overheat again. but im still concerned about my high oil pressure, any suggestions? Also my heat worked for a bit, now doesnt so probably needs a new core, oh well worth a try.

 

I learned that in the 80's and that's why I don't recommend any products like that.


If you can't afford a new heater core you can disconnect it from the system, flush it out both directions again, then clean it out with some CLR but make sure you flush all that CLR out GOOD! Some people suggest leaving it sit for 15 minutes, some suggest 30 min to an hour. It is corrosive to the metal so the risk level is all up to you. Personally I've never had to use the CLR method.

When flushing out the heater core I like to connect it like he does in the first video so there is less mess getting on me and right where I'm working.



I like to use the stop/start pressure techniques that are shown in this second video.






Here's one mans idea of how to do a circulating flush with a mixture of CLR, radiator cleaner, and water in a 5 gallon bucket with a drill powered liquid pump.
I may give this a try one day as it looks a little gentler than the straight CLR method.







How are you flushing the engine? Did you install a plastic flush T and hook the garden hose to it?

Even though the thermostat is stuck open I'd totally remove it and install a flush kit that comes with an inline T then flush the system a few times. DO NOT FLUSH WITH FULL GARDEN HOSE PRESSURE or bad things can happen.

As mentioned make sure the water pump is moving the coolant and check that the fan is operating normally. Make sure the fan clutch has some resistance to it when the engine is warm.


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At no time do you mention bleeding the air out of the cooling system was that a over site ??

These engines are know for air pockets and can be quite cranky !!

They tend to act just like your problem.

 

Heating issue was solved by flushing out the block with the screw under the manifold. (gunk buildup), so there is no more overheating issue. however i do still have high oil pressure, how do i go about solving this?

 

Have you put an actual gauge on it? Or are you going off the factory gauge?

 

factory gauge

 

To me factory gauges are just as bad as an idiot light. Some people might say "Oh it's dangerous" and think that they all leak but I have alot more trust in mechanical gauges.

I'd at least get a GOOD electronical aftermarket gauge with its matching sending unit to see how much pressure you really have. Electronical gauges have to be matched with the correct sending unit or the readings will be off.

 

X2. If your really worried about it get an aftermarket gauge.