1997 Sierra 1500, 5.0L, 110k. Just sent my truck to the repair shop as my truck was nearly overheating ( ~ 260 degrees!) within 10 mins of local driving after loaning my truck to a friend.... long story short - yet another water pump gone (this was apparent as there was water coming from the weep hole). Repair shop tells me I should replace belt, belt tensioner, upper and lower radiatior hoses, clamps and do a radiator flush. I can do some of this - BUT- never done the belt tensioner replacement nor the flush. (they wanted almost $600 to do all)...... I told the shop just to do the water pump (for $286 plus tax) and I'd do the rest. So. I'm looking for advice on the tensioner: Ive replaced the belts via the tensioner, just not the tensioner itself. Is this hard? I dont have my truck w/ me yet to eyeball the effort. Secondly - can I do a flush myself? The repair shop told me my case was "extreme" and they didnt know if my system would ever truly get cleaned... whats the best way to do this ? Sorry for long post. Newbie here. thanks in advance, Mike

 

Tensioner is easy. Just 1 bolt holding it in. Before flushing it, go buy some radiator cleaner from the parts store. Its a Prestone brand. Run that in ur system for as long as 10 to 15 mins or if it overheats then go ahead and drain it. One thing, if you dont much about what ur doing, it would be best to let someone else do it. Otherwise you run a higher risk of injury to urself.

 

Ruffneck, thanks for the advice. I'm pretty good mechanically as long as I have a plan. going to get the radiator cleaner now and will let you know how it goes.

Here's my plan:
1) dump the cleaner in the radiator (fill with water if instructions say so).
2) replace radiator cap
3) start engine and let idle for 10/15 mins
4) shut engine off & let cool for a while
5) open radiator cap
6) open lower radiator drain plug and catch all the nasty stuff in a big pan
7) turn on water hose and pour in top of radiator to "flush"
8) put hose in lower drain value and reverse flush (as best as possible)
9) replace plug
10) fill radiator with water, run for 10 mins to circulate
11) repeat steps 4-10
12)drain water from radiator
13) fill radiator up with 50/50 mix per manual's specs

does this sound right? is DexCool mandatory, or can I use the normal green coolant?

thanks for all the help!

 

That sounds right friend. Just keep doin that until clear water comes out. Then you could go back with either of both. Just dont mix. Dex-cool is mainly for aluminum based motors like the LS1's. But the green works just as good. In fact a lot of people have been getting rid of the Dex-cool and goin to green. Just get your mixture right. 60% coolant 40% R.O. water. Oh and also Change the T-Stat. Get the whole system knocked out with fresh parts.

 

Update - I've successsfuly replaced the T-stat and skipped the belt tensioner for now. Flushed engine for the first time and after 5 times of repeat filling with water and flushing, I'm still getting blackish fluid when I first open the radiator drain ****. After flushing with hose from top and bottom it soon goes clear, but next time I repeat, its black when draining. When looking at the drained water mix, it is definitely black - lots of residue.... Where could this be coming from? Can my system be that nasty? Can this be oil? It doesnt feel like oil - not very thick nor slippery nor anything floating separately from the water. What do y'all think ? PS - This is such a rush working on my 'ol truck.