3B overheat on long hills. Help!

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Oct 31, 2012
British Columbia
I had the frost plugs in my N/A 3B replaced in October and since then I have had a persisting issue of temperature spikes when climbing up long highway hills. (Squamish to Brohm lake for example)

Since then I have replaced my:
Rad cap
Fan clutch
T-stat OEM 82 degrees
Water pump
Various hoses including the lower rad hose
Flushed heater core
Installed an mech. Water gauge

And still no results.

It runs beautifully on highway flats and through town, even slight inclines but when I drive long inclines such as Squamish to Whistler it seems to not enjoy it so much. When it reaches the 110 degree mark i usually pull over and let it idle to cool. I’ve owned this truck for 7 years and it belonged to my mom before that and never had this issue with it other than a clogged radiator years ago which was recored.

The coolant is quite sludgey and dark. I’ve flushed it multiple times and had it professionally done but it stays that way unfortunentely.

It seems like the system is not holding pressure very well. It never came out of the overflow tank until recently when I tightened some hose clamps and now it seems to overflow so it holds a tiny bit of pressure when spiking but not much. The upper rad hose is easy to squeeze. Heat blows hot when at normal op. temp but then blows less warm when engine temps spike.

Timing marks are at factory settings.
Planning on doing a rad pressure test and take it in to a shop for a HG test. One fellow recommended Kieran in Langley. Does anyone know if he’s still working on cruisers? Seems as though I need a genius to help me and I’m more than happy to pay!!

Any other suggestions?
Given the state of your coolant, and that the radiator is very old and that you've already covered off on the other obvious causes.. I'd be moving straight to a brand new radiator and a massive effort to flush the block and heater core (or cores) out as aggressively as possible whilst the radiator is out.
Might you have a leak allowing oil into the coolant? I’ve seen head gaskets fail before where the compression is fine and coolant doesn’t leak but oil does.
Might you have a leak allowing oil into the coolant? I’ve seen head gaskets fail before where the compression is fine and coolant doesn’t leak but oil does.

It doesn’t appear that I am loosing oil into the coolant. The coolant doesn’t appear oily nor does my oil level deplete. My coolant level remains the same as well. The radiator stays full.
I vote to replace the radiator. I noticed quite a difference in engine cooling when I finally swapped in a new one.
Although you've replaced your fan clutch, are you sure it's operating correctly? Do you hear the fan start to roar when it engages as it gets hot? Next time you start to overheat, stop, shut the engine down and try to spin the fan by hand, it should exhibit serious resistance to turning if it has engaged correctly. I went through a similar problem (especially on the first few miles of the Duffy lake road out of lilloett) and it took three or four brand new clutches from certain suppliers to finally get the correct one for a 3B.
the coolant should not be as you describe it, wonder if someone ran pure water in the system for a while which promoted rust. I would flush the system until water comes out clear and then replace with proper mix of water (distilled water & coolant). If the truck is mechanically sound it appears your radiator is a target for replacement, assuming your fan shroud is in good shape and the other parts of your cooling system are good. If you have coolant overflowing on simple things (boiling over) then I would suspect a head gasket.
Any progress on this?

Yes. The issue has been solved. I essentially replaced everything in my cooling system starting from the cheapest (rad cap and t stat) to the most expensive (water pump, fan clutch etc) and even all my hoses. The culprit ended up being a partially clogged radiator. I had removed it and sent it to the city to be re-cored into a 4 core radiator. I then reinstalled it and flushed my system and heater core with a garden hose and ran de-ionized water and a coolant flushing compound on 3 different occasions until the water I was flushing through my system ran clear after each flush. Then I proceeded to fill up with Toyota “red” coolant. Since then I have ran the truck 5000+ KM and have had no issues :) my truck no longer persists past 90 degrees celcius, even on those bigger hill climbs. Hope this helps!
I asked because I had a similar issue last weekend. Pulling up a mountain it started running really hot and overheated. I let it cool and had to add water. No issue with that. When arrived home I drained the coolant and it did not look particularly bad. When I refilled it I found it would not take coolant easily and I had to pump the lower hose to get it to accept coolant. For sure not right.
I suspect I have a partially blocked radiator myself.
I suspect I have a partially blocked radiator myself.

Is your radiator one of the double pass types found on B engines? Its when you have the inlet and outlet on the same side and the coolant is circulated from right to left and back to the right again. The inside collapses with age and causes symptoms like you have.
One of those infra red temp guages pointed at different parts of the radiator would confirm it. One side will be cold and the other normal.
It is. Although there was nothing unusual in the coolant when I drained it. I would have expected som garbage if it was in fact destroyed inside. Maybe it is just a small part of it.

I will see how the temp acts whe run for a while.
I dont think they do put out garbage, I think its probably a metal frame that comes loose. But Ive never seen one on the inside. Another quick way to tell is to spray water on the radiator lightly. It should evaporate fairly evenly if all is good.
I have a question about coring one of these. Since the water enters and exits on the same side, if one was to solder in a 4 core center section, would that be weird? Most radiators enter and exit on opposite sides to force water to flow through the entire core.

Thoughts on a recore?
The core shouldn't matter. It wouldn't be any different for a double-pass or single pass radiator. The difference is in the end tank with the inlet/outlet. There's a separator plate in that end tank to force the water to flow through the core. A little more info here including the effect on flow rate and pressure drop.

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