Radiator efficiancy or lack there of

[Taz]

well summer is here again and I am getting hot AGAIN Since I have now done ALL the standard repairs I am thinking the Ron Davis is causing the problems. I checked the temps at the inlet (upper) and outlet (lower) of my Ron Davis Radiator today. Ambient air temp in the shade was 85 degrees. Sitting at idle (for 20 minutes HOT) with hood open temp was taken using temp probe at
-front inlet corner of radiator core...215 degrees.
-front outlet corner of radiator core...175

That is a differnce of 40 degrees

I have:

-New clutch
-New Head Gasket
-Toy truck fan
-Super charger
-Cleaned injectors
-180 degree thermostat

My question is...does anybody have the same set up with the 3 core brass Toyota radiator that could take these temps under similar conditions? Dan don't you have this same set up more or less?

 

[cruiserdan]

I have a blower and newish OEM three row radiator. What method are you using to measure the temperatures?

 

[Brian Macgyver]

Your in/out temps are OK. Is the radiator flow slow? At-rest readings can deceive.
Your rad is big, but has anything happened that could plug it up? Rad passages are small and small debris can plug it up. If flow thru is slow it can't cool.
Questions to ask yourself are; When and how fast does it heat up? Is it only when at speed with the AC on? Or is it right away after cold startup, within a few minutes?
Slow flow in the rad will cause heat-up at high load such as highway speeds, especially with the AC on. A stuck t-stat will heat up right away, and a slow t-stat will act like a slow rad flow. Has there been any event that could introduce debris into the system to plug the radiator? Have you replaced a head gasket, a water pump or thermostat? Have you used silicone on any part of the cooling system? (Silicone produces strings of left-over material that plug up radiators.)
Change the t-stat first and recheck. In it still heats up, check the radiator.

 

[Brian Macgyver]

P.S.
I bought a new three core rad for my Celica a while back. It originally came with a single core. It worked great until I lost a bearing in the head. After replacing the head (and scraping gasket material and other debris into the cooling system) the rad has been plugged and will not cool at speed with the AC on. I should have washed that stuff out. Also, many people have replaced a pump or t-stat using silicone and had the rad plug up soon after. Silicone is good in many places, but can be very bad in cooling systems. It is not used by most pros.

 

[Taz]

I will take some pics today of where and how I am taking the temps. Thanks for your help Dan...do you have the 3 core Toy radiators in stock I might be needing one?

Brian...I have a new 180 degree thermostat (I updated my first post)
I just replaced my head gasket (preventative) and every thing was very clean with the radiator fluid. I have also changed the fluid 4 times in the last 10000 miles .

my over heating is mostly at slow speeds with air temps of 70-95 after 95 I am just plain HOT fast or slow.

 

[Tools R Us]

Blue hub clutch or aftermarket? Ring fan or nonring? When the clutch engages can you feel airflow pulled in to the radiator from the front side?

 

[e9999]

215F coming in is very high for idle after 20 mins, unless it was very hot to start with. that doesn't sound normal to me...

 

[Taz]

the fan is a non ring fan...from a toyota truck Dan knows the part #...blue clutch new and working, don't ask how I know but lets just say my finger nails are really short At Idle the fan is pulling enough air to suck a blue shop towel up against the condensor.

 

[IdahoDoug]

Taz,

Changing the fluid several times won't undo the damage if crud got into your cooling system from the head work. First time you started it up, crud went through the system and got lodged where the passages are smallest - your rad. Best is to flush the block free of crud BEFORE filling the system using the block drain. Dunno if you did that, but if not that would likely be at least part of your issues.

DougM

 

[Taz]

I replaced the head gasket due to over heating...it didn't change a thing. I am still over heating just the same. What is the best way to clear the radiator of crud just to make sure?

 

[clownmidget]

Mark, I'd pull the radiator completely out of the truck and have a good radiator shop "core" it. That shouldn't cost that much. But if you're going to throw that Ron Davis rad in the bushes let me know where...

 

[Brian Macgyver]

Try a little mechanic's trick. Put some vinegar in the system (about 30%) and run for 5-10 heat/cool cycles. Then flush very thoroughly. All vinegar acids must be removed from all components. Include all heater cores and hoses. It is best to open t-stat and other openings and rinse deeply. Chips, chunks and cloudy fluid will emerge. This will be the best that you can do to clean out the system chemically.
This can be a two-edged sword. If your radiator is plugged with calcium you will clean it out. But if the block is lined with calcium deposits they will be displaced and added to the deposits already stuck in the radiator. The radiator is made up of very small passages that effectively act as a filter, catching small particles. It tends to plug up.
The upside is that if it doesn't solve the problem, the calcium build-up in the block will be dislodged and removed to the radiator, which can be replaced without major work. The down side is that you have only a 50/50 chance of solving your problem with a simple cure.
If you still have slow flow symptoms, you will have to replace or manually clean out the radiator. At least the goop will mostly be in the rad, and not in the block.
In future, you may want to use the cleanest water possible in the system to help prevent such problems.