I just went through this. I replaced the water pump, did the inline mod, and got an electric fan. The fan was a disaster on the highway (shroud trapped hot air... try 226 degrees or driving with the heat on to get to 210), my old water pump was fine, and the inline mod worked. But I also had an extra, old, radiator and a new one. The temperature difference between the flushed, old radiators was a about three degrees, but the difference with the new radiator was ten degrees. I got it for 156 shipped from buyautoanything (I think). IMHO 210 is not too high but you can keep it under 200 even in Texas at 102 ambient.

If your temps rise at higher speeds it is probably the radiator if you are using an otherwise stock, clean setup with the inline mod.

Also, I ran it without the thermostat (inline mod housing empty) and did the same route every time.. swapped radiator three times in one week... and the temp without the thermostat was the same as with. It just took a little longer to warm up.

I don't understand bypassing the throttle body so I don't have an opinion on that. I'd like to know what that does for you.

 

Got a new radiator in this sucker Charlie.

I started her up again with the heat on high and the cap off. She got up to 215F before coming back down. She started idling at 199 eventually. Noticed the expansion tank was near empty at that time. Made the mistake of revving her up again after that. May have put more air in the system. Temperatures went up again after that.

 

Okay found another leak this time its in the thermostat housing. I thought I had it tight enough but maybe not. What side should the rubber grommet go on for the thermostat just to double check? I just put on the thermostat without much thought about it.

 

Yikes there went my theory... you've got a new radiator. The rubber on mine faces the engine (spring side) but I don't know whether that is right. I just put to toward the side of the housing with the fattest lip.

 

Its all good seemed to have figured it out.

After some trouble shooting I think I may have this figured out. I retightened the housing and flipped the rubber gasket. This seems to have made a difference.

I just went for a 30 minute drive and I'm consistently running 183-188.6. Regardless of AC. Though I did see it go up to 190 and 194 before coming back down.

I was running 186 on the highway with the AC going full blast. Pretty damn incredible I must say.

When I got back home I let her idle for about 10 mins. Stayed at 188.6. Gave her a rev then turned the AC on, she stayed at 186.

I will say though that highway driving doesn't seem to chill the coolant as much as used to but I assume that's because the overall temperature has been brought down so much.

I should have done this mod a long time ago. This is a good and relatively easy thing for people to do and it can at the very least shield you from an overheat if something were to occur.


Thank you guys

 

Those are great temps. Congrats!

 

Hey Charlie perhaps im not out of the woods yet.

I don't think this has anything to do with the thermostat but Im getting a temperature spike upon start up it seems. This was occurring before I did the inline mod as well.

I just drove her around town and when I started her up and drove off the temperatures climbed to 221 before cooling down. However when it cooled it cooled down rapidly. It went to 221 to 188.6 in probably a few minutes. It never spiked again on the rest of my short trips just now.

It seems to happen when the truck hasn't been driven for at couple hours if not overnight. What would you try trouble shooting?

Its got a new radiator, fan and clutch. I also checked the pulleys for play and found none when I had the belt off. I thought I got all of the air out but I guess I could try again.

 

Okay that's a really high temperature. Wow. Almost as though the thermostat takes a long time to open. I had three thermostats (because they are so cheap and because I am a hoarder) and was experiencing something similar so I put them all in a pan of water and watched them open at 180. I put the fastest opener in my truck. But if you are sure your thermostat is okay then I'd say that would have to be air somewhere in the system (which you should see in the expansion tank after awhile, with lowered coolant levels) or the "heat sink" effect that causes temps to rise for a time after you turn your truck off... but that doesn't seem to describe the problem you are having.

When you were bleeding air out did you run the heater? I'm wondering if you might have air trapped somewhere. That was my issue, but even with that I never saw a post-inline-mod temp over 208 (after I fixed my shroud problem).

 

I've tried bleeding the air in two ways.

1. The cold bleed method. Where you raise the expansion tank and loosen the bleed screw.

2. Expansion cap off. Start the truck and run the heater on max heat.


But for number 2 I only ran the truck for a few minutes. How long should I let it idle? Should I rev the motor when doing this?

 

Okay so I think I may have fixed the temperature spike. I spoke with RoverMasterTech and he made reference to swapping the throttle body hose with the radiator return hose. I bypassed mine and our conversation basically eluded to this effecting the thermostat. He may chime in here in detail.

But I decided to take out the superstat 45858 and I cut the jiggle pin off with a wire cutter. Then I enlarged the hole to 3/16. It seems to cool properly now on start up. Fingers crossed this is the solution.