I've noticed this problem since about last February.

I have a singleplane EFI intake, with the raised coolant crossover. My CTS is in an adapter, (3/8 to 1/2") into that crossover.

My guage CTS is in the left head, as stock.


Problem - my EFI CTS reads around 160 when my guage CTS reads around 230.

I have an IR thermometer, and I can say that the surface temp of the intake manifold is around 140, the surface temp of the radiator is around 110.


So do you think my water temp is really 160 and my head CTS is just reading high due to high exhaust temp?

Or do you think the combination of raised/airgap crossover and adapter fitting is causing a low CTS reading at the intake?

I know my engine bay is hot as crap. My IAT temp is around 120 after just 10 minutes of idling. (intercooler not hooked up yet).

-- Joe

 

Which single plane?

I would not expect to see a difference of that much from head to intake. If rad is 110 on ir gun, can you touch it and feel what temp is by hand?
Also what does rad hose measure? Can you touch it?

My car seems to closely match gauge to intake reading plus ir gun readings. So sounds like maybe your head sending unit is off?

 

i always find the coolant temp senor in the cylinder head reads higher than the intake coolant temp sensor. also the hat from the heads with raise it as well. I run mine from the intake manifold on my setup. also have a fan switch in my radiator which automatically turns my fans on.

 

I can hold the upper radiator hose, no problem. Feels hot but not burn your hand.

Radiator I can touch but it's hot. After a few seconds you have to pull away.

Intake is a pro-products hurricane.



I'm kinda baffled myself. If I aim the IR gun at the area of the head CTS I pick up between 280-300.

-- Joe

 

I'm using ECM to control fan. I had my fans set to come on at 180 intake temp, but by the time the intake hits 180 the gauge in the dash is almost in the red.

So I backed it off to 140 degrees, which keeps my gauge in the dash around 220 or so.

I don't mind running 180-200 degrees, I just don't know what to trust

Thermostat is 180 degrees btw.

-- Joe

 

It may be false reading then. Try grabbing a hose at 200+ deg you'd know its way to hot to handle.
I would move sensor location or try a new sensor.
Mine doesnt seem to have a heat soak issue but i have seen those style sensors used for mat's suffer from heat soak so it may be a similar case

 

Joe, use the drivers side fitting area next to the waterneck on the intake manifold to relocate the temp sensor for the gauge, that is what I did, works like a charm...

 

Hrmm.. I guess I'll do that this week and see what I get.

Do they make CTS sensors in 1/2" NPT so I don't have to use the reducer ?

Thanks!

-- Joe