Going to do the radiator tomorrow morning. Fingers crossed.

 

I would do the Flip test regardless.

Because if rad checks out OK you may want to do the water pump at that time

 

Pulled the radiator on Sunday morning. The lower transmission cooling line was a pain in the knuckles, but I got it to go without twisting the line off. Cleaned it all up and the nut spins freely now. I did the test and water flowed out then slowed then some more came out followed by some really nasty rusty water. So I decided to throw the new radiator in and give it a try.

The upper radiator hose didn't blow up like a balloon this time. Still firm, but maybe that is somewhat normal. After a short drive the I checked the lower hose and it actually felt a little warm rather than ice cold like before, I think that is also good since it means there is flow into and out of the radiator.

The temperature still hangs right about the middle of the gauge, in the middle of the symbol.

Should I be pulling the radiator cap to check fluid or just drive it and keep an eye on the reservoir and temp gauge? I was adding coolant before, but I was also spilling some here and there.

Thanks for the help.

 

I would run it thru a few heat up and cool down cycles, then check coolant level in rad when cold.
It should be right at the top if overflow system is working as it should.

The overflow system is self purging if any air was left in the heads or heater core when refilling.
When engine heats up coolant expands and the now extra coolant, or air if its at the top of the rad, is sent over to the overflow tank, any air would bubble to the top of the overflow tank.
When engine cools off coolant shrinks and pulls only coolant back into the rad because overflow hose is at the bottom of the tank.
So all air should be purged after a few heat/cool cycles.

 

Thanks Ron. That is how I have been checking it and it was always lower than the opening when I took the cap off. I will run it a couple more times than check the level.

If it is low on coolant I have no idea where it could be going. Not seeing smoke, the oil is perfect and it is always dry under the truck. No signs/smells associated with a heater core leak either.

 

Mark the overflow tank level with a piece of tape when engine is cold.
If there is more coolant in the tank after a few heat and cool cycles and some air in the rad then your rad cap or overflow hose could be the problem.
Warm Coolant is going out, as it should, but air is being sucked back in when it cools.

Same thing can happen with a small leak in the engine/rad side, air is easier to move than coolant, so coolant goes out to overflow but air is sucked in when cooling.

 

Marked the overflow tank. After a couple of cool cycles the level appears to be the same. I also checked it after a 10 minute or so drive after it got up to temp and the level was the same. That might be normal, I don't know. I let it cool and checked the radiator and it took about a half a quart. This was the first time I cracked the cap on the new radiator so I supposed some air could have worked its way out. If it is low tonight I think I may have a more serious issue.

Now those darn transmission lines are leaking. I had no trouble before with the old radiator, but now the upper line is leaking all over the place. I can't seem to tell if it is the first fitting that is threaded into the cooler input or the actual cooler itself leaking inside the end cap of the radiator. The line connection looks good. I used pipe joint compound on all threads and they are pretty snug. Any ideas? Wonder if I got a bad radiator?

 

I had a similar problem when I had a 3.0. It turned out to be the lower hose. It has that weird Y at the bottom.

 

For the automatic transmission coolant fittings going into the radiator, I used the white teflon tape. For the transmission lines going into these fittings, I used plummers thread putty, as I wanted to be sure that nothing could dislodge and make it's way back to the transmission to clog anything.

If one of these are leaking now, this will be the reason you are having to add coolant. As ronD pointed out (as well in a thread I had a few months ago), the leaking connector will draw air into the radiator, rather than it drawing coolant from the overflow. Its a shorter resistance "point of travel".

 

Thanks bucko. It looks like it is leaking the tranny fluid from the fitting that threads into the cooler. The line connection into that fitting still looks good. I am going to switch out those fittings for the ones that were on my old radiator since they were not leaking. I will use teflon tape on the fittings and compound on the lines. I was tempted to bypass the radiator all together and use an external cooler, but I have heard that this may cause the transmission to behave poorly while getting up to operating temp.

I really hope this radiator doesn't let coolant mix with my tranny fluid, that would be a disaster. So far I see no coolant leaks from the trans cooler outputs on the radiator, just trans fluid. Also no signs of coolant in the transmission that I can tell.

Because of this leak I haven't been able to put any miles on it to see how much coolant it is using. I did replace the overflow tank line with some high quality hose last night. The old one seemed to be ok, but was really flimsy and old.

I want to thank everyone again for all of this help, I have been learning a lot from all of you.