350 water temperature issue

[JR1986K10]

Hey I recently purchased a 1986 K10 with Gm crate engine, serpentine setup,FItech fuel injection. The temperature is about right with a 180 degree thermostat at the sensor in the intake. The factory sensor is in the head. It gets up to about 240. I have even taken the thermostat out. No change. It also has 3 row radiator with electric fans. They pull air. They seem to be ok. I haven’t been driving it much till I get this sorted out. I have also made sure that it is a ccw water pump. Any help would be appreciated.

I should have put this in my post. There was a mechanical gauge in the truck when I got the truck. It also was showing 240. I bought a new ACDelco factory sensor and put in place of the mechanical sensor. Showing about the same temp. I replaced the thermostat with a 180. Did not help. So that when I removed it to see if that helped.

 

[Handy Andy]

u sure your t-stat is good? throw it in a kettle of water and put it on the stove with a thermometer in the water and make sure it opens up at the proper temp... Another thing to look at would be the factory sensor... may be bad?

Running without a T-stat will make your engine run hot. Coolant will be rushed through the radiator too fast for it to actually cool down.

 

[Daveo91Burb]

You might want to check out my build thread, starting at post #207. With vortec heads I ended up having to put a bypass from my intake to the water pump. I don't think this is your issue, since you say it's still a problem even with the thermostat out, but thought I'd throw it out there anyway.

Seems like since the two sensors are showing big temp differentials either 1) one of them is bad or 2) hot water is collecting in the heads and having a hard time getting out.

 

[75gmck25]

Are you saying that the sensor in the intake shows about 180, but the one in the block shows 240? My first guess is that the gauge/sensor showing 240 is really screwed up. Every time I've had sensors in both locations, the the temp has never varied more than a few degrees between intake and head.

To take out all of the electrical and gauge variables, I would buy one of the cheap mechanical temp guages at the parts store and screw that sensor into the block. If it also reads 240, you have something really wrong with coolant circulation in the engine. If it shows a more normal temp, then all you have to do is figure out how your gauge and sensor are mismatched.

Bruce

 

[HotRodPC]

Yep. my guess is that someone has the wrong sensor in the head OR the gauge is bad. I could see a little variance at the sensor and head, but not 60 degrees.

 

[Charlie]

 

[JR1986K10]

u sure your t-stat is good? throw it in a kettle of water and put it on the stove with a thermometer in the water and make sure it opens up at the proper temp... Another thing to look at would be the factory sensor... may be bad?

Running without a T-stat will make your engine run hot. Coolant will be rushed through the radiator too fast for it to actually cool down.

I should have put this in my post. There was a mechanical gauge in the truck when I got the truck. It also was showing 240. I bought a new ACDelco factory sensor and put in place of the mechanical sensor. Showing about the same temp. I replaced the thermostat with a 180. Did not help. So that when I removed it to see if that helped.

 

[SquareRoot]

My vortec 350 consistently shows a 10-12 degree difference between the heads and the intake. I have an autometer sender & guage in one head and a Dakota Digital sender & fan control in the other head. Sniper sender in the intake. I have switched all three sender's/guages to every possible location and the 10-12 degree difference never changes.

 

[shiftpro]

My vortec 350 consistently shows a 10-12 degree difference between the heads and the intake. I have an autometer sender & guage in one head and a Dakota Digital sender & fan control in the other head. Sniper sender in the intake. I have switched all three sender's/guages to every possible location and the 10-12 degree difference never changes.

How do you like the Dakota controller?
thanks..

 

[SquareRoot]

So far I love it. Looks & feels like good quality, lots of features, easy to program. I have it running my dual 11" Spal fans. Set the on/off for each fan independently and has an ac kick. Better than the pwmm spal unit I had years ago. I also like the adjustable run on after key off. I set it for 60 secs but you can no use it or set it for whatever. Good for the carb guys getting the underhood temps down a little.

 

[Rusty Nail]

Nicely done old top, I never saw that comin!

Wow.


Hay noob!

 

[Rusty Nail]

u sure your t-stat is good? throw it in a kettle of water and put it on the stove with a thermometer in the water and make sure it opens up at the proper temp... Another thing to look at would be the factory sensor... may be bad?

Running without a T-stat will make your engine run hot. Coolant will be rushed through the radiator too fast for it to actually cool down.

Where you been Andy?

 

[Handy Andy]

Where you been Andy?

Crazy Busy, thats where I've been... between work, and my side business, and some other things my wife and I have been planning, I've been just stupid busy... Probably only had my boat out about 10 times all summer.... thats pretty crappy for a guy who owns a walleye tackle business.... We will be better prepared for next season though. Been going around taking pre-orders for next spring so everything will be finished well ahead of time.

I've finally found a bit of time to get back to my 86 gmc though. Did some exhaust work last weekend as well as replaced a leaking intake manifold. All new plugs and wires going on as well. Should hopefully have it running like a dream by the end of this weekend.

 

[Rusty Nail]

Sounds great, thanks for the update. I hope your businesses and things continue to work well -it's good to see ya around.

Don't be a stranger!

 

[fussfeld]

Read this concerning temp sensor placement and other things:

http://www.madelectrical.com/workshop/water-temp-gauge.shtml