Coolant reading

[smokin'6]

Put a new scanmaster in and coolant is reading 195-200 while my autometer is reading 165. With a 165 stat and no pressure being built up in the radiator, I believe the autometer to be correct not the SM. After putting in a new coolant sensor for the ECM, Im still getting the same readings. Any thoughts on the cause, and if I have to live with high coolant readings from the ECM, do you think there is any perfomance loss from the ECM thinking the motor is hotter than it is? At least my fan turns on quick now

 

[Shuterdown]

If you're unsure what the actual temperature is, get a thermometer, take off the rad cap, and poke it in (not touching the sides). You can even use a thermometer meant for checking roasts in the oven.

This will tell you for sure which one is correct.

On a side note, my car wouldn't run a degree under 180 or so with a stock rad, and the fan on all the time. Only when I put a 4-core in did the temp drop down to 168-170.

 

[smokin'6]

Its a four core with the fan wired for high only. I dont believe the car can be at 200 degrees like the SM says and yet I can still pull off the cap with no pressure. Just trying to figure out why the ECM thinks its higher than it is, and if others with SM/directscan have encountered similiar.

 

[bruce]

There are two seperate senders, use a manual thermometer to see which one is correct. Generally, the ECM sender is the most accurate. It uses a dedicated ground, and precsion voltage supply.

 

[smokin'6]

So your saying Im able to open the rad. with the coolant at 200 degrees ?

 

[87ttypeV8]

only if you are resistant to 200* liquids and wont get burnt

you must wait to open that cap or it will be gushing out

dont know how you could test with a thermometer since it is a pressurized system ...

 

[smokin'6]

Yeah, thats the point I was getting at myself, I had pretty much assumed the ECM sensor was off since I was opening the system at '200'. Guess the point wasn't getting across thou

Was trying to find out if others had the same experience or what anyone might think the ill effects of the ECM misreading the temp might be.

But usually I just end up polishing up my typing skills instead.

 

[GrndNatnl]

Where is your Autometer gauge sensor at?

Some people install sensors for aftermarket gauges in different places. The temperature of the water flowing out of the heads and across the intake is the important temperature. Depending on where your water temp gauge is reading from, there may be a variance.

 

[smokin'6]

Ah, good point, but don't you still think that a reading of 200 a little high for a system with no pressure?

 

[GrndNatnl]

Kinda.

I've never taken my cap off when its been really hot, so I'm not sure how much pressure it should actually have. If it bleeds enough excess pressure off into the reso, then it just may not have a whole lot if you remove the cap. I'm not exactly sure how that would work.

The coolant going across the intake may be 200* degrees, but flowing through the radiator, its usually not quite that hot either.

 

[FlyinGN]

You remove the rad cap before you start it . Then start and let get hot with the thermometer IN the rad coolant.

Originally posted by 87ttypeV8
only if you are resistant to 200* liquids and wont get burnt

you must wait to open that cap or it will be gushing out

dont know how you could test with a thermometer since it is a pressurized system ...