1988 jimmy 355 cooling issues

[Andrew Hare]

I had a radiator take a crap on me over the weekend and I replaced it, now I have an issue with fluctuations in temp only while driving and I arrived home from work to a rock hard upper radiator hose. I have no idea what’s going on and I’ve been financially struggling since my wife threw me out and demanded a divorce. Please help

 

[Joel Wilson]

I had a radiator take a crap on me over the weekend and I replaced it, now I have an issue with fluctuations in temp only while driving and I arrived home from work to a rock hard upper radiator hose. I have no idea what’s going on and I’ve been financially struggling since my wife threw me out and demanded a divorce. Please help

I would check for coolant flow and coolant level. I don''t now how many times I've ended up with air pockets that resulted in sometimes drastic coolant temps. Thermostat could be suspect. You are very limited as to what could cause this problem. Radiator, water pump, thermostat, coolant level-ie air pockets.

In regards to the wife and divorce thing, unless you feel you can discuss the problems and iron things out, then I would get a lawyer. And even then, I think I would have a lawyer on tap. Nobody wins in a divorce, not you, not your wife and not your kids. Nobody.

 

[Andrew Hare]

So apparently I had a stubborn air pocket and a blocked heater core, however it has been determined that cause of replacing my original 3 row core radiator with an after market 3 row core aluminum radiator my truck is cooling too well now and was advised to block off most of the air flow across the radiator to combat the over cooling by the new radiator.

 

[6872xtc]

So apparently I had a stubborn air pocket and a blocked heater core, however it has been determined that cause of replacing my original 3 row core radiator with an after market 3 row core aluminum radiator my truck is cooling too well now and was advised to block off most of the air flow across the radiator to combat the over cooling by the new radiator.

I understand the blocked heater core causing issues with purging an air pocket.
I fail to understand the cooling too well idea.
I have a 4 core copper/brass radiator which doesn't give me problems in the winter. The thermostat should handle that. If it's bypassing too much when closed, that can bring temps down.
Now, running downhill for an extended time in below freezing temperatures can cool it off too much due to no heat being generated in the engine.

 

[ZooMad75]

I ran a 4 core diesel size radiator in mine with a 5.3 for years. It is the largest radiator you can stuff in a squarebody. It really was overkill for the little 5.3. As in operating temps at 160-170 degree range when it was hot or cold outside. I still had heat in the winter.

You shouldn’t have to be blocking off the radiator because it’s cooling too well. What kind of temp is it actually running at right now? There’s a real chance your thermostat is stuck open which won’t allow the engine build enough temperature because it’s flowing coolant constantly and not allowing it to close to allow the temp to build.

 

[Andrew Hare]

I understand the blocked heater core causing issues with purging an air pocket.
I fail to understand the cooling too well idea.
I have a 4 core copper/brass radiator which doesn't give me problems in the winter. The thermostat should handle that. If it's bypassing too much when closed, that can bring temps down.
Now, running downhill for an extended time in below freezing temperatures can cool it off too much due to no heat being generated in the engine.

I have a 3 row core aluminum radiator radiator and I wish I had a 3 row core copper and brass rad cause ever since my original copper and brass rad took a crap I’ve had issues with this cooling system running cool

 

[dyeager535]

I have a 3 row core aluminum radiator radiator and I wish I had a 3 row core copper and brass rad cause ever since my original copper and brass rad took a crap I’ve had issues with this cooling system running cool

It has nothing to do with the material the radiator is made of. Something else is up.

Coasting downhill I've seen my coolant temps get a bit under thermostat temp. More quickly when the ambient temp is colder. Only in extremely cold climates is that going to allow significant overcooling even with a working thermostat.

For some reason your thermostat isnt doing it's job. The thermostat governs the minimum temperature of the engine, that's its sole function. Outside of extreme climates, if the engine doesn't get up to rated thermostat temp, the thermostat isnt doing it's job.

If the radiator was that bad initially, a stuck open (or missing) thermostat may have been the case all along, and once you got a radiator that actually works, the lack of proper coolant flow regulation became apparent. I wouldn't expect random fluctuations with a missing thermostat however. I've run without one, and the engine simply ran cold, all the time.

 

[6872xtc]

I have a 3 row core aluminum radiator radiator and I wish I had a 3 row core copper and brass rad cause ever since my original copper and brass rad took a crap I’ve had issues with this cooling system running cool

It could be possible that a chunk of something got caught in the thermostat and is letting coolant bypass. It could be jammed or never get to a temperature high enough to open it and let the debris loose. I would check it.

 

[Joel Wilson]

So apparently I had a stubborn air pocket and a blocked heater core, however it has been determined that cause of replacing my original 3 row core radiator with an after market 3 row core aluminum radiator my truck is cooling too well now and was advised to block off most of the air flow across the radiator to combat the over cooling by the new radiator.

How do you know its overcooling? Are you going off of a factory temp gauge or by the fact that your heater is now not putting out a whole lot of heat? If your heater isn't putting out a whole lot of heat, then I would remove your thermostat and test it in a hot pan of water, Not your wife's best pan either. That, my friend, would be bad. Also, make sure you are giving the engine a chance to actually warm up. With an entire cast iron engine, it takes awhile. In my 76, I could be halfway to the next town before my heater started working.