Overheating

[Dammerung]

Just had my dad take my truck in for the smog check to finally get it registered for the road. It idled for 10 minutes while the dude was getting readings and overheated. What are my options going forward? Boiling out the radiator, filling up on coolant, replacing the thermostat, etc?

 

 

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[jdog]

Check the fan clutch, coolant level, was it actually overheating, possible bad sending unit, bad thermostat, is it open or closed cooling system?

Stock 1988 swb 4.0 ax15 np 231.

[Dammerung]

Check the fan clutch, coolant level, was it actually overheating, possible bad sending unit, bad thermostat, is it open or closed cooling system?

Stock 1988 swb 4.0 ax15 np 231.

Original cooling system and it was overheating. It spit coolant every in the smog shop.


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[Eagle]

1 minute ago, Dammerung said:

Original cooling system and it was overheating. It spit coolant every in the smog shop.


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There are four possibilities:

1. Radiator
2. Thermostat
3. Fan clutch
4. Pressure cap on coolant bottle

First test: Thermostat. Do you know if the thermostat is working? Have you tested it?

 

Next: If you know the thermostat is working, you know it overheats when sitting and idling. What happens when you start driving again? If the temperature comes down again when you're moving, that means the radiator is doing it's job but the fan isn't pulling enough air through the radiator. The primary fan is mounted on a viscous coupling that's intended to improve gas mileage. They go bad over time and lose the ability to drive the fan with enough power to be effective.

[omega_rugal]

overheating while standing still means a bad fan clutch, the problem is airflow

 

when is overheating and spilling coolant everywhere, touch the radiator, if it´s relatively cold to touch, aka you can hold your hand against it, it MAY mean the radiator is clogged OR the thermostat is stuck closed, or there may be lots of rust inside the engine block, the problem is coolant circulation

 

also the stock pressure bottle zucks, it likes to crack and not hold pressure, not holding pressure means overheating, a cap that doens´t seal properly also leaks pressure and causes overheating

 

why everybody go straight to the thermostat? a stuck thermostat causes overheating but come one, it can be it every time...

[jdog]

Because out of all the possibilities it's the one that has the most use and fails more often other then a cap, also usually the cheapest fix

Stock 1988 swb 4.0 ax15 np 231.

[omega_rugal]

and usually people keep throwing new thermostats over and over and never fix the overheating issue...

[jdog]

People usually do, if they would perform the inspection of it instead of assuming it's bad it be a lot better. If they perform the inspection then all there out is hours worth of time and a 50cent gasket.

Stock 1988 swb 4.0 ax15 np 231.

[87MJTIM]

"Been there, done that."

 

My cap gave out and the engine would overheat while idling.  It would cool off if moving (air flowing through radiator).  The fans could not move enough air in 100* days to cool the motor.

 

Replace the cap first.  Get Volvo cap.  Easiest to fix/replace and least expensive.  Once you've done that, drive it around for a few minute to get it up to temp.  Then park it in the driveway and leave it running.  Watch the temp and look for leaks/overflow.  If that fixes the overheating, you are good to go.  If not, then move down the list: t-stat, radiator, etc.