Well after a long wait I finally got an ultragauge for the Disco. This is first time I finally had live numbers for my engine temperatures. The past few months I was hoping that I wasn't slowly cooking the engine or that I had a malfunctioning t-stat(just installed the motorad 180).

So once installed I tested it on a 25 minute drive. I made sure the engine was running long enough to hit operating temp for several minutes(middle of the gauge). I didn't go past 194 F the entire time, this was on the interstate as well. In city driving going 35-45 mph the temperature was consistently 188-190F.

When i took the exit ramp off the interstate I turned the heater on full blast. Temps went down 194-187 F. I drove 45 mph the rest of the way home. It was pretty cold outside if that means anything, 36 F. I was honestly surprised and was expecting to easily make 200 F, but the hottest I got to 194.

Are my engine temps good? Seems like 215-220 is the dangerzone on here and I wasn't really close. I'll be going for a longer test drive tomorrow.

 

Man you crack me up, you have been to hell and back with that truck this year and now after all this time you get a ultra gauge.


Your temp are right on as they should be with all the new parts and fresh head gaskets. Your are one of the only guys I know that would do one head gasket and then the other but I am glad you are able to finally sit back and enjoy it a bit!

 

Do you have a new radiator? Or do others have the same 7 degree shift when the heater core air flow is added? My thought is that a rad in good condition might not have quite that much shift.

 

When I turn the heat on at idle my temps quickly drop from 195 to 188. It's nuts. The heater core in these truck is pretty big so it can transfer a good deal of heat.

 

Heater core is really not that big dude.

 

My point is just that, if you have a big change by adding air flow to an existing small secondary radiator (heater core) - does that mean main radiator is not 100%? In the later D1 and D2 there is no heater core valve, they are always full of moving hot coolant when running. So all you are adding is the blower fan for the heater. Which is no match for the 70 mph one at the front radiator. Perhaps with numbers from a larger sample of members we can come up with a "digital change" value that indicates rad problems. While some of us consider a rad change out chump change and a fun Saturday afternoon, others may not.

 

I understand where your going with it!

 

My radiator is brand new, but the heater core still make a difference. And it is relatively big compared to many other vehicles. The flow through the heater core is constant and once you start pulling air through it with the blower it makes a difference. All that heat blowing into the cabin has to come from somewhere. Seven degrees seems like a decent drop but it is only about a 3% change in temperature which isn't all that much.

 

Ahah thanks man. Yeah I shouldn't have held off on the ultra gauge but I just had a little faith in the truck I guess. Yeah it definitely wasn't taboo to do one HG then the other. However I at the time I only had one confirmed hg leak and I was hard pressed for time. It was close to finals week and I needed to get back on the road. But all in all I'm glad they're changed now.

My temperature readings give me a little more faith in the parts I haven't replaced yet. The water pump/radiator/fan clutch have not been replaced since I got my hands on the Disco at 108,000 miles. So I'm guessing some of these parts have been replaced before. Though I suppose the Motorad stat is compensating somewhere. While I feel better now I'll still be ordering a new fan clutch and airtex water pump soon.

Quick question for you guys. When a water pump starts to fail are there obvious signs, or will the pump just fail completely and will I get a sudden temperature spike?

 

When a water pump fails, it will usually become hot, blow the seal and start leaking. If you are adding water to your radiator or reservoir on a continual basis, then there is a water leak. To see if it is the water pump, you can place a piece of cardboard directly under the water pump at night and check to see if it is wet from leaking water and coolant the next morning. You can also feel the bottom side when the engine is cool to check for leaks. When running the coolant usually leaks from the weep hole on the pump.