60 Overheating from carb not being tuned right? (SOLVED) (1 Viewer)

[DenaliJames]

Cruiser overheating after idling for 5-10 minutes. Creeps up gradually and eventually approaches the red. I verified that it's not just the unreliable gauge with an infrared gun so that can be ruled out. I just had a lot of items replaced including the carb rebuild; I need to have the carb tuned (or learn how to do it properly). I just had the following items done:
*New Rad (CSF)
*New Rad Cap (OEM)
*New Aisin fan clutch
*New OEM T-stat
*New OEM Water Pump
*New water temp sender
*New T-Fitting on firewall
*New OEM Head Gasket (Had the head redone and manifolds planed)
*New Air Filter
*Block flushed
*Carb rebuilt (have not had it tuned yet)

Also worth noting that before I had all this work done it was also overheating. I also jacked up the front and let it run to get any potential air bubbles out of the cooling system. The Cruiser does run poorly and dies at a stop since it is not properly tuned (Seems to be running too lean and will not run with the choke pushed in all the way). Could it be overheating from just not being tuned properly? I do run it with the choke about halfway out so the RPM's are higher than normal, not sure if that could be the cause also. I'm in the process of trying to find someone local who is good as tuning these but wanted to get people's thoughts on the overheating issue. Thanks!

 

[g-man]

I don't see a new thermostat on that list. A stuck thermostat will make it overheat.

 

[DenaliJames]

I don't see a new thermostat on that list. A stuck thermostat will make it overheat. But more likely just an air bubble and it needs to be burped.

My apologies, new OEM T-Stat as well. I'll update the post

 

[g-man]

Is the timing on the BB?

 

[DenaliJames]

Is the timing on the BB?

I will check on that to be sure

 

[g-man]

When you are idling can you put your hand on the upper radiator hose and tell when the thermostat is opening. This should be a sudden surge of water and the hose will turn from warm to too hot to hold with a bare hand. Also it will turn from spongy to tight. If the thermostat doesn't open it can cause overheating. Yes, new thermostats sometimes fail to open.

 

[g-man]

 

[DenaliJames]

When you are idling can you put your hand on the upper radiator hose and tell when the thermostat is opening. This should be a sudden surge of water and the hose will turn from warm to too hot to hold with a bare hand. Also it will turn from spongy to tight. If the thermostat doesn't open it can cause overheating. Yes, new thermostats sometimes fail to open.

I will also check this

 

[OSS]

The engine doesn’t make much heat at idle and the cooling system is grossly over sized for just idling when everything is working correctly.
I agree with g-man, it seems that the coolant isn’t flowing through the radiator.
Attach a vacuum gauge to the manifold to see what’s going on with the vacuum at idle. It should be near 20 inHg at sea level.

Just for a test- you could remove the thermostat completely from the thermostat housing then bolt the housing back together and do a test idle.
Engine should idle stone cold the whole time without a thermostat and never warm up.

 

[ceylonfj40nut]

Do a head gasket leak test with a kit from the big box stores.

 

[Casey E]

never mind see you checked with a gun also

 

[DenaliJames]

Do a head gasket leak test with a kit from the big box stores.

Head gasket is new OEM. Was having a similar overheating issue before doing the HG but before it would only overheat at highway speeds and not at idle. Right now its overheating at idle

 

[DenaliJames]

The engine doesn’t make much heat at idle and the cooling system is grossly over sized for just idling when everything is working correctly.
I agree with g-man, it seems that the coolant isn’t flowing through the radiator.
Attach a vacuum gauge to the manifold to see what’s going on with the vacuum at idle. It should be near 20 inHg at sea level.

Just for a test- you could remove the thermostat completely from the thermostat housing then bolt the housing back together and do a test idle.
Engine should idle stone cold the whole time without a thermostat and never warm up.

Good idea, I haven't checked vacuum yet. Forgive me for my ignorance but where specifically would I connect the vacuum gauge on the manifold?

 

[OSS]

where specifically would I connect the vacuum gauge on the manifold?

At the brake booster fitting on the intake manifold there’s a little pipe jutting off of it that has a small vacuum hose connected to it. That small vac hose is for AC idle up, so you can disconnect it and connect your vacuum gauge to the pipe instead.

 

[Seth S]

Let’s run through the basics:

1. When the temp gage gets to the red does the truck boil over?

2. If you stand by the drivers side fender with the hood open and the truck idling…so the air from the fan is hitting you…do you feel the air get hot for a period of time and the. Cool and then hot and then cool?

3. Have you adjusted your valve clearances
4. Have you verified timing
5. What octane fuel are you running
6. Which spark plugs are you running and what is their gap
7. Any chance you put the head gasket in wrong (it can be done).
8. Is your air filter housing clean(not just the filter)
9. What is your idle speed set at
10. How does the truck start…both hot and cold? Is it a struggle or does it fire right up?

 

[DenaliJames]

At the brake booster fitting on the intake manifold there’s a little pipe jutting off of it that has a small vacuum hose connected to it. That small vac hose is for AC idle up, so you can disconnect it and connect your vacuum gauge to the pipe instead.

View attachment 3030181

Thanks for the info, I'll check the vacuum and report back

 

[CruiserTrash]

Let’s run through the basics:

2. If you stand by the drivers side fender with the hood open and the truck idling…so the air from the fan is hitting you…do you feel the air get hot for a period of time and the. Cool and then hot and then cool?

Curious about number 2 on your list. What is that checking for?

 

[Cruiser Cult]

Curious about number 2 on your list. What is that checking for?

Fan clutch engagement.

 

[Seth S]

Fan clutch engagement.

This and T stat cycling open and closed. If the T stat is working properly it will open and close regularly to allow coolant flow through the radiator. You can feel a real obvious temp difference in the air coming through the radiator between T stat open and closed....its a great low tech way to verify operation

 

[lcwizard]

Cruiser overheating after idling for 5-10 minutes. Creeps up gradually and eventually approaches the red. I verified that it's not just the unreliable gauge with an infrared gun so that can be ruled out. I just had a lot of items replaced including the carb rebuild; I need to have the carb tuned (or learn how to do it properly). I just had the following items done:
*New Rad (CSF)
*New Rad Cap (OEM)
*New Aisin fan clutch
*New OEM T-stat
*New OEM Water Pump
*New water temp sender
*New T-Fitting on firewall
*New OEM Head Gasket (Had the head redone and manifolds planed)
*New Air Filter
*Block flushed
*Carb rebuilt (have not had it tuned yet)

Also worth noting that before I had all this work done it was also overheating. I also jacked up the front and let it run to get any potential air bubbles out of the cooling system. The Cruiser does run poorly and dies at a stop since it is not properly tuned (Seems to be running too lean and will not run with the choke pushed in all the way). Could it be overheating from just not being tuned properly? I do run it with the choke about halfway out so the RPM's are higher than normal, not sure if that could be the cause also. I'm in the process of trying to find someone local who is good as tuning these but wanted to get people's thoughts on the overheating issue. Thanks!

I recently has an Aisin fan clutch that didn't work right out of the box. Second one worked perfect. Don't assume anything. Overheating at idle but not at cruising speed
is usually an airflow issue. If you kept your old fan clutch, swap it since it wasn't overheating at idle before