Engine Temp / Heat

[ZeroData]

I have a question. This is the first expedition I have owned. It is a 98 with the 4.6. At first there was only warm the rear heat was cool. I flush both heater cores. They both blow warm air now. I have checked the blend door action and they both operate as expected. I have put two thermostats in (195 degree). I noticed the fan running full speed almost all the time. I changed the fan clutch today. It now operates as expected. I let it idle from cold for 18 minutes and the ODBII reader showed engine temp of 192. The upper radiator hose was still cold and the heater hoses finally began to get hot to the touch. After 22 minutes the reader showed 200 which then began to drop back down to 194. I was expecting much warmer air from the heat. Is this normal?

Thanks,
Scott

 

[bedrck46]

how many miles on the expy? check the hoses going into and out from the heater cores they both should be close to the same temp. Also check the temp along the return from the heater cores to see if there are any cold spots. It may be possible that the water pump needs to be replaced due to the fins being deteriorated.

 

[ZeroData]

The heater hose in is fairly hot. The return is cooler but not cold. Same with lines from the engine. Water pump was last on the list as I have replace thermostat and fan clutch. I just thought it odd that the engine temp was so low.

Thanks,
Scott

 

[bedrck46]

again how many miles on the expy?

 

[bedrck46]

engine temp seems normal if your using a 195 deg stat and it went to 200 and dropped back to 194 I would say its working OK

 

[ZeroData]

Sorry. Odometer has 203k. Motor was rebuilt but I am not sure how long ago. The water pump looks like the factory one. No water in oil and vise versa. Also after our trips the next two weekends I had planned to flush the cores again.

Thanks,
Scott

 

[stamp11127]

There is a small restrictor in one of the heater hoses, make sure that isn't plugged.
Check flow from the engine to the front heater core if your going to flush the cores again.

 

[ZeroData]

Where is the restrictor?

Thanks,
Scott

 

[stamp11127]

inside one of the hoses at the t connection

 

[ZeroData]

On the in, out or both? Thanks for the info.

Thanks,
Scott

 

[Copper93]

Do you hear any gurgling noise? It's possibl3 you have an air pocket. Park it on a incline with the radiator at the high point and let it run. See if you can work any air out of the system.

 

[ZeroData]

No gurgling noises. Also my driveway is on a 40 degree incline and that's where I let it idle for 25 minutes. Wednesday I will tap into the lines and back flush all the heater core lines and replace the water pump. I've work on numerous other models of cars but this one has me stumped. I'd still like to know what the normal engine operating temp is.

Thanks,
Scott

 

[mjlcobra]

Sounds like it could be your water pump to me.... Check this thread out. My inlet hose was hot as hell, but my outlet hose was only hot from the engine heat. I'd say if you can squeeze the outlet tight for more than 5-10 seconds with a hot engine, the coolant isn't flowing through it.

Link: http://www.expeditionforum.com/f42/very-little-heat-front-rear-21711/

 

[ZeroData]

Yeah I had heard this on several forums. Tomorrow I will be flushing the heater cores again and replacing the water pump. I'll report back what the results are.

 

[mtsumedi]

Awesome, please post pics of the water pump if the fins are deteriorated. Mine is doing the same thing and I'm about to try and figure out what it is.