Hey guys. Are thermostats easy to replace on the 4.3L W VIN engines? I have 88k on this one and I don't think it has ever been replaced (definitely not in the last 30k I have driven it.). I am going to be converting the coolant to Prestone All Makes/All Models next weekend (if I can find a garden hose) using the Prestone Flush n' Fill kit since I have mud in the radiator (coolant was flushed 12k ago) and I would like to replace the thermostat if it is easy enough to get to. I think it might be stuck partially or fully open because I idle the engine for 5 minutes every time I do a cold start and it only lifts 1-2 notches above 100 and then I drive it 2 miles to campus to go to class and it isn't even halfway between 100 and 210 when I park the truck. I would have to drive it a few miles at highway speeds (including accelerating to 4k RPM to get on the highway) before it gets to 200 and stays there. Sometimes it gets to 210, but never goes above that.
I have already replaced the radiator cap, which is what I found out was the cause of the mud since it was the original cap for this truck. I also found the tube between the radiator and overflow tank kinked.
Also if it possible to use the Flush/Fill kit without touching the radiator drain valve? I can't get it to move and I REALLY don't want to break it off and have to take the truck to a mechanic because I really don't want to spend the cash if I can do the flush myself. Is it possible to use a hand pump from the filler neck to remove the fluid from the radiator? Also I can't find in the instructions how to use a flushing agent with the kit. When would I add the flushing agent in the procedure and then get it out? Thanks for any advice on this matter.

 

Another cooling system thread?? LOL

The thermostat is very easy to replace. It's between the throttle body and the EGR valve.

And it sounds like you need to get in there and wrestle with your lower radiator hose. Take off the shrouds if you need to, but you WILL have to drain the block/radiator out if you want an effective flush. You may want to consider fully removing the radiator to clean the junk out of it.

 

Yea sorry about that. I am trying to get this mud out before it causes any damage. I really don't want a repeat of the night we drove this truck 60 miles home from the dealership when the thing lost all coolant and overheated and didn't even make it the first 20 miles. Thank god the dealer paid for a new radiator because it was clearly a hidden flaw that existed before we bought the car. I don't want to mess around when it comes to cooling system maintenance because all that can come of it is expensive repairs.

 

Alright. I called a radiator shop in the area to replace the thermostat and flush the system. I have an appointment next week. I don't have the resources to do all this here (no garden hose and only basic tools). They are going to use Prestone green stuff in the cooling system. Maybe if I can find Purple Ice around here, I will put that in also to protect the water pump so it doesn't have problems anytime soon (88k miles-original pump).

 

Here we go again!!! Mud in the cooling system with Prestone. Radiator is full, recovery tank is full and clean with nice green coolant. Radiator cap was covered in slimy brown crap. The internals of the radiator have some brown slime on it. Oil was clean at last oil change (no milk). No antifreeze smell unless the caps are off. No antifreeze leaks as far as I can see. I thought maybe it could have something to do with the water pump (original as far as I know), so I grabbed one of the fan blades since I couldn't get my hands in there. No play at all (is that how to check a water pump if it is bad or not?). Is there I chance I have something else wrong with the engine? I had the intake gaskets done at 72000. The coolant has less than 4k on it. Also the hose that connects to the thermostat has some yellow stuff between it and the thermostat tube and the hose only has 35k on it (as with the radiator and other hoses). Thanks

 

I have the same thing on my radiator cap. what i know that its the rust coming from the radiator.

 

Good job there buddy...a year old thread...



edit : DAMNIT i bumped it.

 

and the funny thing is that I just had the radiator flushed again a couple weeks ago because the radiator had some slime in it and it was getting past 210 on hills in hot weather. Now it doesn't go past 210 at all and most of the time stays with the needle covering the "2". No leaks at all.

 

that brown slim that keeps showing up in your guys's trucks is coming from the inside of the motor, for some reason the 4.3 blocks like to rust when air mixes with dexron antifreeze, and it dont matter how many times you flush your system it will keep coming back the only way to fix it is to use a certain cemical that GM offers to do a flush with and it will take a few repeated flushes (and half a tank of gas) but it will eat the rust away and stop it forhappening. the best thing that i can tell you to help prevent it from happening is to run basic green antifreeze and get rid of that dexron.(for some reason it only likes to do it mainly with dexron basid on what ive seen over the years.)