Engine temp isnt rising

[79Sea30]

Morning All-
Hoping some of you may have some guidance on a temp issue.

Here's the background. Truck was running fine/temps were great and holding at the 180/190 area when in use. No issue with overheating, or running too cold. I replaced the intake manifold over the last few weeks, and i'm struggling to get the temp gauge to raise to where it was before.

New Parts installed in the last few weeks:
Weiand Aluminum Intake Manifold
Adjusted timing within spec once installed and truck runs great.
Re-filled with coolant.

Within the last 6 months:
Waterpump
All new hoses. Radiator, heater etc.

Issue I'm experiencing:
Temp gauge in truck, raises only about a 1/16" on the gauge itself. Much lower than previously. Truck does not overheat, but seems cold in the engine bay. After running for a bit, top radiator hose is hot to touch, bottom is cool. Heater hoses are hot to touch.

What I've done to try to remedy:
2 New 195 thermostats. Both have been tested in boiling water, and closed as they should. One is MR Gasket brand, and one AC Delco.
Tried to bleed air from the coolant system. Radiator cap on, while coming to temp. Air seemed to escape. Maybe there's more?
Tested the Temp Gauge, and it maxes out like it should when grounded.

What my next thoughts are:
Do another full flush to ensure there's no crap within the system?
Replace coolant temp sensor in block?

I know there's a lot of topics on this, and honestly I'm usually pretty confident with things, but this one is driving me insane. Seems like it's something simple, but I cannot get it to raise more.

Thank you in advance-
Kyle

 

[85K304SPD]

Body ground from engine to fire wall? Sending unit? Try a manual gauge to check the factory gauge.

 

[79Sea30]

Body ground from engine to fire wall? Sending unit? Try a manual gauge to check the factory gauge.

I'll take a look at body grounds. Temp sensor is an option that I need to look at. Going to pickup a simple temp gauge to try it tonight.

 

[Snoots]

You didn't use teflon tape on the sensor did you?

 

[79Sea30]

You didn't use teflon tape on the sensor did you?

I actually have not changed the sensor, so if there is teflon, it's not from me. Being that the sensor worked before the manifold change, I dont think there's an issue there. But I am looking to replace it as another piece that may not be working to it's full potential. Going to try to test it tonight with an ohm meter to see if it's raising with temp etc

 

[Strick]

Within the last 6 months:
Waterpump

Look at the part number or casting to make certain that you didn't get a water pump with a reverse flow (serpentine drive). I have had both cars and trucks in the garage that either the serpentine belt was routed backward or it had the wrong pump, which caused them to run warm/hot. Your post description is a 79 454 which should be v-belt driven; it'd be difficult to get a v-belt routed wrong. So, with the top hose hot and the bottom not, I'd definitely look at the water pump and make certain the impeller is turning right. The only issue with this is that your truck is not running hotter than normal, it is the opposite.

Strickland

 

[79Sea30]

Look at the part number or casting to make certain that you didn't get a water pump with a reverse flow (serpentine drive). I have had both cars and trucks in the garage that either the serpentine belt was routed backward or it had the wrong pump, which caused them to run warm/hot. Your post description is a 79 454 which should be v-belt driven; it'd be difficult to get a v-belt routed wrong. So, with the top hose hot and the bottom not, I'd definitely look at the water pump and make certain the impeller is turning right. The only issue with this is that your truck is not running hotter than normal, it is the opposite.

Strickland

Appreciate that. That was what I originally thought it was as well, but prior to the intake manifold swap, temps were fine. To clarify, I had done the waterpump in the spring, drove the truck for 1500 miles or so, and no issues. Then just in the last few weeks replaced the manifold.

 

[Strick]

Appreciate that. That was what I originally thought it was as well, but prior to the intake manifold swap, temps were fine. To clarify, I had done the waterpump in the spring, drove the truck for 1500 miles or so, and no issues. Then just in the last few weeks replaced the manifold.

Every 454 I've had will nearly cook the paint from the hood. When you said engine bay temps were lower I was stunned. Thermostat temp at 195 should be correct too. This will hold the coolant in the rad long enough to cool so the process can repeat. My 79 gauge barely moves off the first mark, although it does work because it bottoms out with key off. I've used a temp laser and coolant, block, hose and water neck temps are normal. The heater works as well as the AC. I'll quit complaining, thankfully it's not running hot!

Strickland

 

[Vbb199]

I'm not sure what motor we are or aren't working with, or what intakes are being used, but did you perhaps include the heat crossover on this intake, and the former doesn't have one?

 

[79Sea30]

Every 454 I've had will nearly cook the paint from the hood. When you said engine bay temps were lower I was stunned. Thermostat temp at 195 should be correct too. This will hold the coolant in the rad long enough to cool so the process can repeat. My 79 gauge barely moves off the first mark, although it does work because it bottoms out with key off. I've used a temp laser and coolant, block, hose and water neck temps are normal. The heater works as well as the AC. I'll quit complaining, thankfully it's not running hot!

Strickland

No doubt. I was in the same exact place you're thinking. To clarify, the gauge does work, and does increase, just not nearly where it should. Driving me insane .

Kyle

 

[79Sea30]

I'm not sure what motor we are or aren't working with, or what intakes are being used, but did you perhaps include the heat crossover on this intake, and the former doesn't have one?

It's a Weiand intake, made for the peanut port heads. OEM, had the crossover, new intake has it as well, but the felpro gaskets have restricters on them to limit the crossover. I have electric choke on it.

Kyle

 

[Snoots]

Sorry. I had a brain fart. Sensor is in the head

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[79Sea30]

I was thinking about something just now. I did replace the thermostat neck too. There's two bleeders in it, but I never removed and sealed. Do you think they are loosing pressure and not allowing it to fully pressurize?

 

[Radiohead]

Is the stat stuck open?

 

[Strick]

Do you think they are loosing pressure and not allowing it to fully pressurize?

Pressurizing the system allows temps to go beyond the boiling point of water at atmospheric pressure. I don't think that the problem is with an air pocket or bleeding as with newer systems. The cap is the highest point in the system and that's where the air will want to go. After being pushed out of the radiator it should evacuate to the overflow tank...or ground...depending if you have a tank or not.
I just put a 6.2 Diesel in a K5 a few weeks back. It has a monstrous radiator with engine oil cooler, trans and an additional p/s fluid cooler. I let it run for a couple of hours at higher idle and it never got over 180 on the cap. The temp gauge only read on the first mark too. It was an 86 Silverado, decked out.
The owner would not sell to me either!

Strickland