SOLVED: Diagnosing/replacing a leaky radiator + flushing coolant (for the inexperienced GMT400 owner)

[slow_c1500]

I’ve been flushing the block for hours now and I’ve gotten the water itself to be clear but it always has some small amounts of rust bits no matter how long I do this. Is it very important that I get every single last bit of rust out? I mean it’s been way dirtier in there for 28 years and the truck has never had problems with overheating. Should I be worried about the little bitty rust bits in the bottom of the block or no?

 

[1998_K1500_Sub]

I’ve been flushing the block for hours now and I’ve gotten the water itself to be clear but it always has some small amounts of rust bits no matter how long I do this. Is it very important that I get every single last bit of rust out? I mean it’s been way dirtier in there for 28 years and the truck has never had problems with overheating. Should I be worried about the little bitty rust bits in the bottom of the block or no?

It will never be perfect. I’ve drained coolant containing sand, out of a fairly new engine block, that was left behind during manufacture.

I was actually quite shocked at the amount of crap that came out of a relatively new engine.

 

[slow_c1500]

Ok the block is flushed clean enough, and I am still waiting on the new rad. My owners manual says I need to add GM coolant seal tabs into the radiator when I fill the coolant, (it didn’t specify how many tablets but someone on another thread said 2) but I’d need to order those online which would further postpone getting the truck back on the road. Do I have to add the tablets at the same time of adding coolant, or can I add them a few days later?

Or are the seal tablets even necessary with green coolant? This is the same manual that says to use dexcool and we all know how that has gone.

 

[movietvet]

IIRC, the sealant tabs are for aluminum blocks. I could be wrong though.

 

[slow_c1500]

My manual says to add them. But idk if I should trust it because it is assuming you are using dexcool, and I am using orielly green.

If I did need the tablets, is it ok to add them a few days after filling it with coolant, or do they both have to be added at the same time?

 

[movietvet]

I would not put them in. If you want to wait a few days and do further research, should be ok.

 

[slow_c1500]

when it comes to filling the system with coolant again and burping the air out, does that need to be done on level ground? (I have the truck on a slight incline right now). Obviously I will get her on level ground when I’m filling the reservoir to the correct level, but what about the filling/burping process?

Also, is there anything I should do about the air that will be in the transmission lines? (Because new radiator)

 

[movietvet]

when it comes to filling the system with coolant again and burping the air out, does that need to be done on level ground? (I have the truck on a slight incline right now). Obviously I will get her on level ground when I’m filling the reservoir to the correct level, but what about the filling/burping process?

Also, is there anything I should do about the air that will be in the transmission lines? (Because new radiator)

When I have the time, I will elevate the passenger front side above level and SLOWLY fill the coolant and when it will take no more, I will let sit overnight with cap off. Then the next day, the coolant has always been low. I then fill SLOWLY again and start engine and let it idle and get to normal operating temp and top off and cap it and drive and bring back and let cool down for about an hour. Then I open and top off if needed, hardly ever does. An old mechanic told me to do that and I have never had an air pocket when refilling that way. If you have an air compressor, there are fill equipment you can use that work great.

 

[slow_c1500]

I don’t have a jack so I won’t be able to get the passenger side higher, I’ll keep that in mind though for later.

I was thinking about filling the block first (to minimize air pockets in there) through T stat hole, then reconnect upper hose and fill the rest thru rad cap. Then let it idle with fan on hi temp, slow speed to burp out air. Then top off overflow tank. Would this method work as well? And would it be more/less effective if done on slight incline? (besides last step)

 

[movietvet]

I don’t have a jack so I won’t be able to get the passenger side higher, I’ll keep that in mind though for later.

I was thinking about filling the block first (to minimize air pockets in there) through T stat hole, then reconnect upper hose and fill the rest thru rad cap. Then let it idle with fan on hi temp, slow speed to burp out air. Then top off overflow tank. Would this method work as well? And would it be more/less effective if done on slight incline? (besides last step)

You can drive it up on something, after you get it all back together and before you fill it. That short amount of time will not overheat the engine.