Alright time for an update, I "burped" the radiator, but I am not sure if I did this right, the water level would go down for a few seconds then come back up, it went through this cycle about every 30-60 seconds. I feel the water flowing through all the hoses as well.

I started to overheat slightly this weekend while towing about 1500lbs in my trailer, I was on a 90 minute drive and about 75 minutes in I started to go up a little above 210, it peaked at the next line which I believe is only 225 but once I turned my A/C off it cooled right back down.

This is the first time it ran hot since I flushed it out and put the new radiator cap on.

The overflow tank is still empty, and checking the coolant levels again it still looks full but when I do the "burp" I still get that same cycle of the coolant level dropping down then coming right back up to the cap.

Any ideas?

 

Starting to think the bottom half of the rad. is plugged up

 

I can feel water flowing through each of the hoses, including the lower hoses. When I pulled all the hoses off I could put the hose into them and it flowed straight through.

 

Not sure but it could be possible that the lower lines flow from one rad tank to the tank on the other side of the rad could be plugged, not letting the rad cool properly

 

What you may want to do is completely remove the radiator from the truck and flush it out while it's out. I did that to my radiator over the summer when I had to pull it to replace my a/c condenser. I flushed the radiator in both directions and got all kinds of crud out of the bottom of it. After that, reinstall it and see how it does.

 

This is pretty easy to check...just let the car warm up and feel the radiator with your hand to see if it's cooler on the bottom. The crud sinks to the bottom and seals up those tiny slits that the coolant has to go through. If they are clogged it's almost impossible to clean them out and requires replacing the radiator. If can try removing the radiator, turning it upside down and tapping it with a rubber mallet while flushing with a hose but it rarely unplugs the slits.....at least I haven't had much luck doing it. Bring back the old days when we could rot out a copper core radiator with acid.

 

Thanks for the tips I am going to pull it out today after work and flush it out again. I will check first to see if it feels cool at the lower half.

 

Sorry for the delay I finally got around to working on the blazer again after a week of running normal temps I overheated again today, it went to about 3/4 of the way to hot this time around.

Now when I pop my hood the metal hose that goes in where the thermostat is has a small pinhole that is spraying out coolant, is that supposed to be there or did that metal piece crack?

I am not feeling ANY waterflow in the lower hose now, when I was before. I decided to try and "burp" the system again today, after 10 mins of running with the cap off I noticed the water finally sucked into the radiator and I was feeling hot flow on the other hose but still now flow on the lower hose, it dropped back down to 210 for now.

Any ideas? Should I put another thermostat in to see if this one is bad already?

 

The thermostat housing, (water outlet) should not be spraying coolant. If it does, it needs to be replaced: Murray® Climate Control 85168 - Water Outlet | O'Reilly Auto Parts

When the engine is at operating temperature, the upper hose should be ~200F. The lower hose, going into the engine, should be ~130F. As the thermostat regulates, coolant flow starts and stops. When the coolant temperature equalizes/stabilizes, you should feel it circulating all the time.

Have you checked the fan clutch? It acts as a thermostat for the radiator. If it does not lock up at higher temps, the engine can overheat, (mainly at idle & lower vehicle speeds).

 

There is a small pinhole on the water outlet, it shoots coolant about 20ft and is making a huge mess all over my motor now. I will stop at orielys after work today and get that part.

How do I check to see if the fan clutch is working?

I checked the lower hose and it felt empty, I could easily squeeze and flatten it and there was no warmth at all, could this mean my thermostat is not opening or my waterpump is bad?

On another note, on my way into work today after about 5mins of driving it went 3/4 of the way up, I made a hard right turn at a light and all of the sudden the guage dropped back down to only about 1/4 and wasn't even full operating temp at that point, a few minutes it ran at 195-210 the rest of the way into work. No coolant overflow yet, been shut off for about 15 mins so far. This truck is mind boggling at this point.