I replaced the blown 6.2L with a new 6.5L bought from chev dealer in 1998. Has approx 3000 miles on it now. Up at speeds 65 or so it wants to run over 200 degrees and climbs higher, can't tow anything without high temps. Its not a turbo truck. Please help!

you need to verify that the gauge is reading accurate first. either with a mechanical gauge or an infrared reader

is it possible that the 6.5 engines water pump turns opposite direction than the 6.2, and the coolant just isn't circulating?

only way thats possible is if you took the serpentine belt pulley off of the water pump and put a Vbelt pulley on it. other than if you did that everything should be working.

I appreciate the info on the serpentine pulley, but the 6.5 motor came from chev.( factory engine) thus I had it installed in the place of the old 6.2L, so it has the v-belts.

was the water pump switched over? if not i bet someone put the v belt pulley on a reverse rotation water pump!

Maybe I'm wrong but if your water pump wasn't moving any coolant you'd be seeing way over 200F

it does run over 200F when it's up to speed 65mph and would continue to climb, but I've not let it get near the red. I just slow down, also I'm in the country and have'nt taken it but 10 -15 mile rides so far. the radiator was checked when I had the engine installed. Also put a 180F thermostat in it. I don't know anything else but to get a new water pump for troubleshooting purposes. That would be a 6.2 water pump for the 89 surburban.

oh if it was a 6.2 water pump for a 89 then its not that since it would be the right one.

sorry for the confusing line, I mean't that I would buy a water pump for an 89 6.2 and install it on the 6.5 thats in the truck now and see if it cures the problem. also can you tell me something I read about a backing plate with the water pump?

What about it?

sorry for the confusing line, I mean't that I would buy a water pump for an 89 6.2 and install it on the 6.5 thats in the truck now and see if it cures the problem. also can you tell me something I read about a backing plate with the water pump?
Yes, the backing plate for the reverse-rotation (serpentine) water pump has different bolt holes than the standard-rotation (v-belt) pump. The 6.5 engine and even '88-up 6.2 engines in C/K pickups use serpentine belts, while the v-belts stayed on '88-'90 6.2 engines in Blazers, Suburbans and "3+3" (crew cab) pickups. Thus, all the confusion.
You would think a dealer installing the engine would know better...:p: but even so, check the simple stuff first, like the fan clutch, the airflow through the radiator, injection timing, etc.

well I bought a waterpump from napa tfw44100 that fits the 89 surburban 6.2 engine, but it won't bolt up ( its different pattern ). So, please help me with a part no. that will fit the 6.5 engine with v belts application for my 89 surburban.

6.2 water pump will bolt up to a 6.5 without a problem. Before wasting a bunch of time, start with the basics. First, what brand of thermostat did you buy? If it isn't factory gm or Robert shaw, I would chuck it. The factory or robert shaws have much better flow than the other junk out there. Next, remove thermostat and place it in water on stove and check opening temperature and closing temp with an accurate thermometer, it should open close to 180 and also close close to 180. Next, check your radiator for cleanliness, inside and out. If it can't flow water, it can't cool it. Next, check condition of fan clutch, make sure it doesn't keep spinning when you shut off engine when warm. Next check your injection timing, do you hear diesel rattle or is the engine overly quiet. Quiet means timing is retarded, you might need to advance it slightly. Lastly, if your engine only has 3000 miles on it, it isn't broken it yet and new engines will run slightly on the warm side. Water pump doesn't even make my list for hot running engines unless someone sold you the wrong direction pump. Good luck

will the backing plate/ timing cover from a 6.2 bolt onto the 6.5 block, allowing me to install the 89 6.2 waterpump on the 6.5 motor. this will in turn pump the water in the right direction.

yup.... bolts right up..... how much is your ip turned up? if you have to much fuel it will burn hotter as well.....

think it's stock setting. problem I think has been the waterpump on the 6.5 motor was turning for the serpentine belt ( clockwise). so I'm thinking the waterpump for the 6.2 my year model truck ( 89 surburban) v belt application which is counterclockwise rotation will fix my problem. But I think I'll need the correct plate to bolt the waterpump to.