engine temp switch

[74chev4x4]

OK just got my new 350 in the truck took it over to have the headers fit to the pipes and noticed my temp gauge in the cab is not working now when it was with the 454 before motor swap.  I bought a new sender for the 350 but is there one for a temp light and one for the gauge, this was the case on my toyota and I blew the guage because I hooked up the sender for the light and not the gauge.  Hopefully this makes sense. Also I ran if for prob 15 min each way barely doing 40 mph noticed my rad hoses never got up to pressure not sure if the tstat is not opening or if I didn't drive it enough to get it to open, just scares me cause the temp gauge is not working and I dont want to warp heads on a brand new motor by overheating.  Any adivice from u guys is always appreciated thank you!

[78 Chevyrado]

OK just got my new 350 in the truck took it over to have the headers fit to the pipes and noticed my temp gauge in the cab is not working now when it was with the 454 before motor swap.  I bought a new sender for the 350 but is there one for a temp light and one for the gauge, this was the case on my toyota and I blew the guage because I hooked up the sender for the light and not the gauge.  Hopefully this makes sense. Also I ran if for prob 15 min each way barely doing 40 mph noticed my rad hoses never got up to pressure not sure if the tstat is not opening or if I didn't drive it enough to get it to open, just scares me cause the temp gauge is not working and I dont want to warp heads on a brand new motor by overheating.  Any adivice from u guys is always appreciated thank you!

There are specific "dummy light" and specific gauge sending units.  If I remember right, they do have different connectors between the two.  It's possible to have gotten a new bad unit;  it happens from time to time.

It sounds like possibly the thermostat may be stuck open.  when stuck open it makes the engine take a lot longer to get up to operating temp.   If the thermostat was stuck shut, it should have overheated pretty quickly.

[74chev4x4]

I would have known if I overheated it right I was taking it real easy coming back from the shop?

[74chev4x4]

ok fixed that the wire was loose and temp gauge is working now.  So the gauge goes right to red after a few minutes of idle.  I have no pressure in my radiator hoses, but there is coolant in the block because I had a bunch spill out when I changed the temp sensor.  Not sure what else to check the water pump is new and so is the thermostat so I'm guessing its one of the two?

[74chev4x4]

just boiled the tstat and it opened up so now what is the radiator clogged
?

[Lt.Del]

i'd run it without the tstadt just to rule it out.   see what the guage does.
could be the water pump.  since it is a new engine, could be the gaskets (head, intake, whatever) may be covering some coolant arteries in the engine. 

[74chev4x4]

sorry meant new to me, it was rebuilt about 15k ago, I put new valve covers oil pan water pump and intake on it.  So I just drained the coolant and ran water from the top of the radiator on the drivers side and it came flowing out the bottom hose on the pass side so the rad is not clogged.  The wp is new which means that it can still be bad, anything else I should check before pulling the wp?

[VileZambonie]

It's not actually overheating just the gauge reads hot? You probably installed the wrong sending unit. There is one for the gauge and one for the idiot light as 78Chevyrado already pointed out to you. What part # did you install? Use the one from the 454 if you still have it.

[74chev4x4]

vilezombie man I need ur help, I think I have the right sending unit the wire was messed up is all part # wt203 borg warner I believe.  There is no flow in this system, I pulled the water pump looked down in it with a light and can see all the blades moving and they all look fine.  I stuck the hose in both ports on the block where the wp mounts and blew water in it and it comes back out, doesn't seem to blow from one side to another though not sure if it should?  So Im stumped, I keep hoping in the back of my mind that I didn't overheat it this morning when I drove it.  I pulled the heater hose going to the wp and there is no coolant in the heater hose?  Also does it matter which hose goes where on the firewall for the heater core I have the top hose going to the wp. Sorry for the 50 questions man I just wanna get this thing done tonight.  Thank you

[VileZambonie]

Did you fill the system and bleed it before you closed the system?

[74chev4x4]

When I first filled it I didn't burp it if thats what u mean.  It was too loud with just headers to do that and I didn't think about it this morning  .  I should have been able to do it anytime after that right?

[VileZambonie]

Fill it through the intake manifold with the t-stat removed. Put the thermostat in and fill it the rest of the way through the radiator. Run it until the thermostat opens then put the cap back on. Get one of these too

http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=4111

[74chev4x4]

gonna go get one right now, thanks man! So would I have known if I messed my motor up this morning?  didn't get on it at all and pulled over a few times. 15 min drive there and 15 back with about an 45 min cool down in between?  Thanks again

[VileZambonie]

I guess you'll find out when you get the system filled up

[74chev4x4]

yea true, one more thing, when I was running water throught the coolant holes where the wp mounts up should it have come out the other side or do those jackets just go on one side like the one on the left only goes around the left cylinders and does not connect to the right collant jacket or is this my clog?