[Background: Truck heats up to 100° C within 5 minutes, 103° C after 15 mins with heater on high (weather has been very hot recently). Not losing coolant. No visible leaks. Thermostat replaced 6 weeks ago, radiator replaced by PO a year ago. Viscous fan clutch appears to be OK. Condenser fan not working. PO paid to have coolant pump replaced in 2010 (I have invoice) but one of several mechanics who have looked at it recently said the pump appeared to be original.]

Yesterday drained (green) coolant, flushed radiator both directions--some scaling flakes (old t-stat had heavy calcium build-up coming from lower radiator hose; new one still clean). Flushed cylinder block until water ran clear--clean coolant and nothing else came out. When reconnecting hoses, I noticed that the upper radiator hose plastic T connector, which was black when wet, but now dry, it had started to develop a yellow-brown scale which got heavier, more opaque, and flakier within minutes (see attached). Tried to scrape a little off but it appeared as if the plastic were disintegrating. Hoses did not show a similar scaling, only plastic T. Reattached everything and filled system with Prestone radiator flush (not stop leak, just flush) and 1.5 gallons distilled water (wouldn't take anymore). Ran truck 2 or 3 minutes, temp went up to 60° and it threw Pending Fault Code P0135. At that point, I decided to stop and seek advice before proceeding (I had planned next to drain system again and refill with Peak 50/50 and Water Wetter).

Thanks in advance.

 

P0135 is heater circuit for an O2 sensor, not really related unless you bumped connector or filled it with water.

Prestone is Sodum citrate (citric acid), a common flush product. I would suspect that your radiator is so full of junk that you needed to run for the full 10 minutes like the instructions said, with heat on as well.

The radiators are so skinny that any crud inside starts to block them off. You can eval the performance of your radiator with an IR thermometer, measure fins at top and bottom, should be within 10F. More clogs equal cooler rows, very little hot coolant inside so same air flow cools them off. Bet the rest of the radiator looks like inside of that T. Because they are so skinny flush and rod out is not always practical as a fix. As a preventative, yes.

PO may have replaced radiator with used one. PO may have used tap water or well water. New rad is about $200 (Rock Auto Nissens brand). 180f stat would be a good thing to have, but get the real Rover one, not Motorad.

 

Thanks for your advice. Will check for temp difference in radiator fins. The Prestone flush directions say run for 10 mins for light treatment or to leave it in for 3 days and drive truck lightly if system has been neglected. Would you advise the latter? I used distilled water.

 

What you may find is that radiator is so clogged up that the hot flush treatment does not make a big enough difference. In previous Rovers they used an expensive copper and brass radiator, the side tank could be unsoldered, and the calcium rodded out. The aluminum ones have a plastic side tank, it becomes brittle with age (and the tiny hose fitting will snap off if you look at them). On this type of radiator it is usually not cost effective for a shop to touch it. If your temperature test confirms a sludged radiator, new ones are $125 - $200.

Some commercial rad shops have a hot citric acid flush that runs the liquid thru there and separates out what is removed on each pass. Home rad flush hopes to put most of the stuff in suspension, but how much of it is removed when you flush, and how much is just circulated everywhere else to coat the inside like a paint is up for discussion.

 

I see your point. If the debris loosened and held in suspension by the flush can end up evenly coating the entire interior of the radiator like stucco (it would seem, in my case), running the vehicle, and thus circulating the same concoction through the engine block, heater core, thermostat etc for 10 minutes, let alone 3 days, doesn't seem like a good solution (if you will)--it would extend a diluted version of the problem to the entire system.

If the current radiator fails the temp spread test, a new one it is. Will seek install advice at the time--can't imagine getting the fan clutch out of there. Thanks for the quick reply. Needless to say, your knowledge and time are appreciated.

 

If your mileage is at or over 100,000 miles and you have scale, you will need to replace the radiator and switch to a 180- degree t/stat.
When back flushing and or filling your system, always use distilled water so you don't build up more calcium again.

 

Get a Nissens radiator from rockauto.com if in the states.
$230 shipped.