okay- So the Overheating issue with my 98 D1 will not seem to die, quit or led me in the right direction for correction.

Issue: The truck warms up nicely, runs perfect and idles perfect and the needle is at 1/3. After driving normal/intermitant hills and stop & go (all in the same drive cycle), The engine will still run normal (no overheating what so ever needle at 1/3). However about 30 minutes into a drive cycle, when I come to a stop at a long light she starts to overheat, yet the engine still idles normal. The temp will start to climb and once it gets just over 2/3 way, I'll throw the heater full blast and it will drop right down to 1/3. The heat coming out is very hot.

Here's the items and the exact order in which I changed out the parts, reason why & addition extra "love". All Items are now functioning:

1. New Viscous Fan (OEM)- Was very easy to spin when cold.
2. New Cooling fans (aftermarket 1,00 CFM each)- not coming on with A/C. Also hosed out both radiators (A/C & Engine) lots of junk stuck in it.
3. New T-stat (OEM)- just for piece of mind. Install in correct direction and with the imprint of "top" at the top in hole (I said Hole)
4. New Temp Sensor for ECU (OEM)- corroded inside only.
5. New Temp Sending unit for gauge (OEM)- corroded in/out- even replaced the "push-on" connector since it also in bad shape.
6. New Water Pump (OEM)- Also Completed a flush (before new pump install) & bleed after (on an incline).

When I completed the Head Gasket, I checked all the hoses for cracks, clogs and damage. All pertaing to the cooling were in good shape.

So what next? Do I man up and let the so called experts at it?

 

Sounds like you need to add new radiator to that list. You've gotten to everything else. You are doing fine no need to go to the dealership.

Edit: I just read that your electric fans do not come on with the A/C. Even when the AC is on "low"? That could be a problem. Also you may want to get an ODBII scanner that reads live data to see what the exact temps are that you are dealing with.

 

I had this problem with another car. It was the radiator. This happened to be a Jag and believe it or not, every time the car was taken in to the stealer for service, the procedure was to add a packet of Barr's Leak to the coolant. Needless to say, the rad got blocked. A radiator shop or many A/C shops can verify if the rad is blocked and either rod it out or replace it. I replaced mine with one off of eBay and all was fine. Dealer will add another 500 bucks just on GPs.

 

I always start with the free things, like making sure the radiator fins aren't clogged with debris which you did second. Time now to take the radiator to a radiator shop and have it rodded.

 

I may have not read closely enough but is this problem occurring all the time or only when you have the A/C on? The A/C without the electric cooling fans running will cause it to overheat.

 

Take the radiator out and have it cleaned and rodded. I had to do this on my 97, cost $50. Most likely your overheating is caused by the A/C fans not coming on this time of year. Check your relays.

 

Does this happen with the a/c off? You shouldn't be running those aftermarket fans if they won't engage at operating temp in town and or with the a/c on.
Deal with this first.

 

All,

Sorry it was a type O in my first post.

The fans (Now) come on when I turn the air on Low (or any setting). I replaced them BECAUSE they were NOT coming on with the A/C. Since I replaced them they are now working when the A/C is turned on at any setting. They also produce 1,000 CFM Each, not 1,00.

With or With out the A/C the overheat condition still happens. So I guess I'm leaning towards the Rodding or replacemnet of the Rad.

 

-I just realized I'm not sure if the fans come on while driving around town. Maybe I need to check the relay.

However I thought the Overheat relay was the same relay for the A/C operation. Isn't it the green relay on the passanger sidewall of the foot well?

 

With the AC off you shouldn't need the AC fans running to keep the engine at the correct operating temp. I know they are supposed to come on if the temp goes up, but I see that as a backup system. A properly functioning cooling system will keep the engine at the right temp.