Let me preface this by saying that in my overexcitement to get back to running, I Jerry rigged a puncture in my top radiator hose with duct tape. (The new hose arrives tomorrow)

Earlier in the year, my truck was running between 206 and 227 degrees depending on speed and how high I was running the heater.. It reached a pinnacle when my water pump went out, taking the viscous fan and top radiator hose with it.

FYI I have hit red on the stock temp gauge twice..

This weekend I swapped out my water pump, and fan clutch, and added a 180 deg t-stat hoping that I would be back to normal..

This evening I wanted to check the temps while idling Like I said I taped up the top radiator hose and fired her up. After 5-10 minutes I was running at about 186, then I gave it some gas. Soon after I heard a high pitched "whistling" (I'm assuming this was pressure coming out of my duct tape work). At this point I looked at my ultra gauge and I was running at 230!

Checked under the hood, and there was steam coming from under the radiator cover, and the radiator hose was super hot.

My question is, what is most likely causing the overheating? Head Gaskets? Radiator? Something else?

-Patience is wearing

 

Duct tape can't hold pressure, and pressure is required to keep coolant in and prevent it from boiling.

Once the system is repaired, please double check the serpantine belt route.

Purge all the air out of the system.

Repeat test, watching the Ultra Gauge. Like a hawk. At 212F the electric cooling fan should have popped on.

Others have used the 180F stat, and run 190F - at 80 mph.

 

Thanks Buzz, I'll check the serp belt again tomorrow. I did take it off and on today when adding sealant to the 11mm bolts for the water pump that I forgot over the weekend.

 

You would be wise to quit driving it today, these engines do not take to over heating and you will cause damage.
Get your new hose installed, bleed the system, if you know how and then let it warm up. If it starts getting hot make sure the electric fan is working at 212 degrees.

 

I haven't driven it in 4 months.

Hose just came in today. Will swap and bleed tonight.

 

If my fan seized previously, and I just swapped it out for a new one, should I also add a new fuse?

I read somewhere on here that when the fan seizes, it tends to blow out fuse 5.

 

When the fan siezes, it goes to what is called "locked rotor amps" or the most it can draw. Usually it is fused below that level of amps for safety. Examine / test fuse. Replace fuse if you think it is cracked, etc. Fan can come on ahead of 212 if AC is on. But not like a D1 where it comes on at same time AC is turned on.

 

Never drive with defective parts or even attempt to run it.
Bad things happen.

When you put the A/C on - you should get an AUX fan starting.
That needs to be fixed as it will come on when you go above
210 Degrees - no matter what.

Your fan clutch - replace it with a Hayden HD clutch.

You may also want to replace your radiator.

I have done all the above and I don't even run a gauge in my truck now.
If I pull into a parking lot with the A/C off and I have a fan running, then
I have trouble.

That is how I figure out the health of the cooling system.
Of course, the ultra gauge is nice too.


Good luck.

 

so all he has to do is replace every piece of his cooling system, and never pull into a parking lot with the AC off and the fan running, and he will be all set.

 

Cooling System Diagnosis 101

1. Got coolant that is not dropping in level when checked at cold start every day? (No leaks) No visible leaks?

2a Got white smoke out tail pipe after warm up? (Head gaskets)
2b Got water in oil (head gaskets)
2c Got oil in coolant reserve bottle? (head gaskets)

3. Serpantine belt route correct and no squealing? (water pump don't wanna run backwards)

4. Paper towel will get sucked against the grille? (fan blades on right direction)

5. Radiator temp when warmed up within 10F top to bottom? (not packed with sludge)

6. Good quality thermostat tested in pot on stove before install? (open at wrong temp)

7. Hoses not swelled like sausages (rotten, full of water inside the rubber, about to pop), hoses not rock hard (from steam pressure)?

8. Coolant not Dexcool? (Turns to mud with poor service by others)

9. Coolant cap holding pressure? (still has pressure when you take cap off for cold system inspection, a paper towel zip tied to the overflow line stays dry, no coolant loss)

10. Electric fan runs when it should, spins freely, has good fuse and relay.

11. Fan clutch when warmed up, spun, released, coasts to a stop in well under 1 revolution.

12. Temps read with scanner, not guessed at with the "keep dreaming" factory heat gauge?

13. No sounds like gurgles and bubbles in pipes under dash when driving? (air or exhaust gas in coolant).

Most coolant system testing requires no special tools. If you have a D1 you can have the radiator rodded out and acid flushed. On a D2, owner manual says change coolant every 2 years or 30,000 miles. So if you have a Disco 2 with 120,000 miles, has the coolant been changed four times? If the Disco is 12 years old, has it been changed six times? No? Well then the possibility of a radiator flush doing much is also greatly diminished.