So, After 3 long months I finally got my Atlantic British engine installed. My dad and I started it up and followed the break in procedure.

We were to let it rev at 1800 rpms for 25 minutes, which we did, and then drive it around for an hour to further break it in. During this drive my temperature gauge went very high (but this was after about 15 minutes of idling and driving).

We checked the coolant and all was well. We got back on the road after allowing the truck to cool down a bit. We drove close to home just in case of anything, and the temperature gauge now stayed dead center like it is supposed to. We got on the highway and it was perfect the entire time. I then idled for 5 minutes in a driveway and it was fine. Then, when going to get back on the highway, the gauge went high again. I immediately shut the truck.

What's weird is the truck doesn't feel like it is over heating. It runs fine and doesn't radiate a lot of heat when the hood is up. The coolant doesn't gurgle at all either. It is as if it isn't over heating at all. Plus, my two auxiliary fans do not come on at all, even when the truck is shut down. With my original engine my fans would run for a minute or two after I shut the truck, only during very hot climate. We checked the fans and they are working. I turned on my AC and they come on. We also tried turning on the AC to see if it affects the gauge, and it didn't. Which means the fans aren't cooling it even when they are on.

Fan clutch is fine. Radiator is good. We changed the thermostat (fail safe). I am thinking it is the temperature sender..? Mine is original. The sensor is good, but the sender is bad? Which is giving it wrong readings?

I am just guessing here. Any advice?

Otherwise engine runs fantastic and smooth as silk. Drives great. However, nothing is ever easy for me or my dad. So..gonna change out the sender today..any other advice would be greatly appreciated.

spike

 

Sounds like air in the cooling system. Try a good bleed. Did the temp spike suddenly?

 

I would say Air too. Don't spend many thousands on a new AB engine and cheap out on a temp gauge. Spend $15 on Amazon and buy a Bluetooth ODBII reader for accurate real-time temp readings.

 

Did you follow air bleed procedure?

Run right front wheel on a ramp or curb
Remove plug in read and cap on overflow ( engine cold)
Run engine till it reaches temp and stat is open, top hose will be hot to touch
Raise idle and you should see water and air bubbles flowing good in rad. With idle up top off at coolant bottle till no more bubbles / coolant coming from plug on rad , reinstall plug idle normal, off ramp , top off bottle as needed

When the stat opens you will lose coolant cause there will be a pocket of air behind it

Do not use fail safe stat, mine failed within months

Use the OEM type with the bleeder built in

Do not use gauge on dash it shows cold and overheat, ultra gauge works great

 

A small block Chevy Stat works well, just drill a 1/8" bleed hole in it

 

There is also the one in the tech section for 180* stant

 

Thanks for the advice guys

I did this entire procedure and then drove. Temp was perfect for 10 minutes. All of a sudden it started creeping up. I made a sharp left turn and the gauge went from hot and right back to the center in less than a second.

It was fine again another 10 minutes or so and then started creeping up again.

I'm gonna get an ultra gauge and use that to see what is really going on.

 

It goes up randomly. I drove for 15 minutes and it was fine, and then it started creeping up. Then I made a sharp left turn and gauge went down to normal in less than a second. I drove another 10 min or so and gauge was fine. Then it started creeping up again. I shut the truck and its been sitting since.

 

Getting and ultra gauge tmro and also getting a new fan clutch, even though mine has resistance. I may as well replace it. I am pretty sure it is original.

 

How old is the rad?

Engine codes?

Clean grounds at batt good