temp difference from t-stat

[70b7duster]

Just picked my car up from being aligned after installing my HDK suspension :burnout: ...Driving home temp got up to 220°. Car has new champion radiator and dual electric fans. Put the temp gun to it, and the radiator side of the upper hose reads 180 and the t-stat side is 200 is that temp difference normal or do I have a t-stat prob

 

[grumpuscreature]

Why isn't your bypass hose hooked up? I can see a loop from the water pump connection to the water pump heater hose connection and a plug in the intake manifold water passage. The purpose of the bypass hose is to allow coolant to circulate in the block until the engine has warmed up enough for the thermostat to open. The way things are now the thermostat never has a chance to fully open and stay open and the coolant in the block is going to be overheated. Pull that plug in the manifold that is just to the left of the top left corner of your temp gun in the first picture, replace it with the proper fitting, and connect the bypass hose from the large nipple on the water pump to the new fitting. While you're doing that you will need to pull out another plug in the manifold water passage and install another fitting so you can loop the heater hose properly. Try NAPA for the fittings, you can use the plugs for thread size...

 

[70b7duster]

Thanks for the heads up. The parts stores are a joke around here. Anyone know the plug size or have a part# for the nipple on an m1 intake

 

[grumpuscreature]

I think the bypass is 3/4" NPT to 1" hose and the heater hose is 1/2" NPT to 5/8" hose. Take your plugs with you for comparison or look on this page...

http://www.summitracing.com/search?...cending&keyword=intake manifold hose fittings

Also noticed that your temp sender is in a reducer adapter. The heater hose will go into that hole and if you pull the plug just to the left of the temp sender, the sender will go into that hole with no adapter. Hope this helps...

 

[Bad Sport]

It also looks like you have teflon tape on the sender unit, teflon tape should not be used there, a good non hardening sealer would be better.

Some say that the teflon tape can interfere with the grounding process and give you false readings.

 

[nm9stheham]

Mmmmm, lack of bypass will delay the opening of the t'stat, and make it operate erracticly when outside temps are cool, but once open with coolant flowing around it, then t'stat will open properly. But it is indeed best to fix it right.

I would suggest to the OP to pull the T-stat while he is at all this and make sure the 'button' faces into the engine; it could well be in backwards and would cause this problem.

Also, for best temp readings paint a patch of flat black paint on the surfaces being measured. I would also susepct that the rubber hose will run a bit cooler on the outside versus inside (as oppsed to metal) so it would normally read a bit cooler.

 

[Darter6]

Yep rubber hose will read cooler than the metal reading. Also in school we were taught that a stat of what ever(say 180 degrees) "Begins" to open at 180 but may be 10 degrees or so higher when fully opened.

 

[SBeeMan]

I'm new to small blocks. So if I'm not running a thermostat at all I can do away with the bypass hose & plug the holes? It's a drag car,so one less thing to fail.

 

[70b7duster]

Got the bypass installed and replaced the t-stat w/ this high flow from mr. Gasket. Will post results this weekend hopefully