Are there any posted specs of the gallons per minute (or hour) that the OEM pump produces?

With that you could run a flow test on the heater input hose with an open heater valve and have a rough idea what it's doing.

Josh

 

After a 72 hour cold soak my EOT sensor reads 2.5* higher then the ECT sensor.

When the engine is warming up the coolant temp leads the oil temp by about 10* until the thermostat opens, at that point the oil temp slowly passes the coolant temp.

 

Might want to determine which sensor is off and change it out, but a 2.5 degree off set isn't much.

Do you have a coolant filter? That is usually tied into the heater hose (supply) and returns flow to the degas bottle. Maybe another way is to simply observe how well your heater works on a really cold day to see if it is getting good flow (along the lines of what Bullitt was suggesting).

 

No coolant filter. I've debated putting one on. Coolant is flushed every 1.5 years and I've never had any debris in it. Truck has 62k on it so coolant has been flushed every 12k. The heater gets so hot it can burn my feet through my shoes. So maybe I am getting good flow.
I will test my oil and coolant sensors against the trans and IAT2 sensors and post the results.

 

Thinking out loud .............

I wonder if you could remove the vacuum from the heater control valve and see if the flow through your heater core (with the blower off, so that it isn't removing any heat) would affect your ECT or your ECT / EOT differential? I guess what I was thinking is: If the coolant flow is marginal to begin with, then routing more coolant flow through the heater core would probably rob it from somewhere else. Maybe that would show up in a slightly (maybe noticeable) higher ECT / EOT differential .... ???

 

I'll give it a shot this weekend. I plan on trying as many things as I can within reason.

I know it probably sounds stupid to try and fix something that's not broke, but I would like to be able to prove that the cooling system is healthy.

 

Here are current cold soak readings.
EOT 39.7
ECT 39
TFT 40
IA2 38

So sensors appear to be fine

 

Nothing wrong with that spread Justin.

 

Yeah its not bad. My minor hints of OCD try telling me otherwise.

I saw a post on diesel site a few years ago about measuring the return flow and supposedly it gave indication of an efficient water pump.

 

I'm running a BPD water pump for about 2.5 years now no problems. Replaced it when we did the head gaskets and all the other upgrades.

 

OK guys, had a chance to work on the truck tonight.
It was time for another oil change, so I broke my routine. Normally I loosen the oil filter til it pops up and just leave it there to drain. Well, in a hurry I yanked the filter out to find it was dry.
I pull out the flashlight and look in the filter base to see nothing under the oil cooler bypass cap. I tear out the standpipe and the bypass cap to make sure. Nothing.
In a panic I look around the bottom and think to myself that my oil cooler ate the valve. I head over to my spare parts to start a search. Turns out, when I had all parts layed out on a table installing a new oil cooler, egr delete, blue spring, etc., the valve fell out and I chalked it up to being the old brass valve in the fuel pressure housing, I tossed it in the bag and never looked back.
I finished up and took her for a ride. Started right up after about 2 seconds of cranking. Drove for about 1 hour to find my deltas of 6. My ECT was 184* and EOT was 192*.
Well now I'm much happier. And I figured my water pump must be fine. I feel like crap, but have a sense of relief.
Now I guess it will be time to tackle the STC fitting and change out the oil cooler base gasket.
Thanks for the replies and ideas.

 

184 ECT and 192 ECT is a difference of 8 degrees or am I missing something?

Josh

 

Just testing you. My bad your right, I meant 8 but typed 6.

However, this morning, temps were ECT 184* and EOT 190* . This time a true 6*.
Thanks for the correction

 

Is this with a newer t-stat?

Josh

 

Looks like I need a new one. Its a new OEM bought in April last year. It has 2500 miles it. I think my original one held higher temps. I can watch the coolant temp come up to 192* and then drops down and settles in between 184-186.