i ran it at the strip for several runs, no problem ran 200-210 the whole time. then on the way home i was cruising about 65-80 mph for about 20 miles, came to a stop light and raced another truck, and got the check coolant temp light directly after i pulled out of the throttle. i never checked the temp before the race. so i pulled over and read it with the v2 and it was 255. went down to 230 in a few minutes. so i turned back onto the road with her at 230 and as soon as i accelerate to speed it shot right back up to 248. and stuck around 248-250 the whole way home. i didnt feel any loss of power, and my boost and egts werent out of the norm. my coolent hose was soft so i dont think i blew a head gasket.

so is it normal to get overheated after a night of drag racing or not? also 255 isnt hot enough to damage anything right?

alright, i took it for a drive and it heatedup faster then normal,got to 190 in about 4 miles of normal driving. then i gave it a full throttle run and it shot right up to 210. then continued to gradualy climb to 230 and stayed there until i parked it. it idles a little rough now too.

seems like it warms up at the same rate even after 180 deg, maybe a stuck t stat? would it be alright to just pull the primary one out to see if its the problem before i buy 2 new stats?

maybe a t stat. have you ever removed your grill and sprayed out the radiator?
how full is the fluid?

iv been playin around with the t stats for a while... first thing i did was boil em to see if they open at all, and they barely crack at over 200 degrees. so i put a regular gasser 160 tstat i had in the front and left the back alone, very little change, still ran 240 everywhere but at least i could hold highway speed at around 245 now. so then i took both out and just ran it oped to make sure this is my problem or not, it didnt seem to make a big difference, but i didnt let her cool first. my test run with it open started out at 215* and quickly went to 235 and stayed, but i was driving faster then before to see how rapidly it would heat up. little improvement but not back to normal. i will have to give it a test run tomarow from a cold start to make sure.

also my fan clutch will not kick in... by 250* i expect it should be on right? iether way it normally never needs the fan to kick on so i doubt this is my problem, just another problem to deal with if i ever tow anything and one thats biting me in the ass now since the rest of my cooling sytem obviously isnt up to par.

my fluid is fresh, flushed it out for the second time just 6k miles ago, probably 65-70% water the rest regular green coolent.

Make sure the radiator is not stop up

you might want to look at your fan clutch a little more mine kicks in way sooner than that it never gets above 210 no matter what i do! And like the other guy said make sure the radiator is cleaned out really good.

i have cleaned the radiator before, but il check it again.

I can hear my fan at about the 210 mark and it will level off around there empty or loaded. 230 is the highest mine has ever got.

yeah check the fan

fan should not be of concern on hiway, except when towing(heavy load going up hill, slow speed)

what do ya make of this?

http://i33.photobucket.com/albums/d53/kfx400rob/th_truckcoolingproblem002.jpg (http://s33.photobucket.com/albums/d53/kfx400rob/?action=view&current=truckcoolingproblem002.flv)

Could be water pump not pumping. Just my 2 cents

yea pretty sure its the pump, anything else i should check before i go ahead and buy one?

great idea on adding the video.

pretty good video too aint it

alright, can anyone make sense of all these options for me?

http://catalog.autopartsgiant.com/ShopByVehicle.epc?q=2001-GMC-Sierra--500--Hd-V8--400ci--6.6l--Diesel--Turbo--Vin--1&yearid=2001%40%402001&makeid=31%40%40GMC%40%40T&modelid=7685%40%40SIERRA+2500+HD&engineid=28497%40%40V8-400ci+6.6L+Diesel+Turbo+Vin+1%40%4028497&catid=2@@Belts%2FHoses%2FCooling&subcatid=34@@Water+Pump%2C+Fan+Blade+%2F+Clutch&mode=PA

first off is the delco 252 838 "water pump kit" basicaly the midsection of the pump with the gear bearing and impeller or does it not come with the impeller?

also there's 2 delco pumps listed, whats the difference?

and lastly, how about the cardone one for $104, cheap Chinese crap or what?

You do not need the housing I got a remanned pump at napa for like $90 bucks havent had any problems

You do not need the housing I got a remanned pump at napa for like $90 bucks havent had any problems
Yep.

is the one you get at napa chinese or what? im not so keen on running an off brand pump, this pump is only 11k miles old and im thinking the only way it could have failed so fast is it wasn't a delco unit. kevin, how long have you had your pump on, does it seem to be good quality?

Almost a year and a half and 24,000 miles it is a remanned factory pump not a chinese copy it looks exactly like the one that came out of it.

A new ACDelco will run almost $400

we've had ours at close to 240 one day. we were towing up the mountains into alberta. so it was a bit rough

it doesnt leak out of the weep hole and it doesnt make noise though?