Heat question: At what temperature ... DIY heater core removal

I am trying to sort out the heat issue in my van 2003 passenger van. At 145 degrees my air is blowing barely warm. I didn't get to 185 degrees because I got busy but should it be hot at 145? I will get my van to temperature later and see if it blows hot but I suspect my thermostat is stuck open because the van takes forever to warm up. I did the hand test on the heater valve and all three hoses to the valve are hot so I think maybe thats not the issue. I get 0-12v on it as well so I know the ATC is probably ok too. I didn't do a test on the pump yet and thats next for me as well as getting the van to running temperature.
 

Aqua Puttana

Poly - Thread Finder
:idunno:

My 2004 and 2006 both will put heat into the air ducts pretty quickly. I don't believe in idle time to warm an engine after starting. I start the engine, let the oil pressure stabilize, and drive gently until the drive train warms up. Truth is I drive pretty gently all of the time.

We live 4 blocks from a freeway. Assume 45F ambient (because that's what it was the last time I bothered to check.) By the time I have entered the on ramp and driven maybe 1 - 2 miles I can feel heat from the face vent when I put my hand over in front of it. Not a bunch of heat, but noticeable. The engine temperature gauge has *maybe* moved up a bit. For certain I get heat out of the cabin ducts before the engine temperature gauge is 145F.

At these times the ATC dial is typically set about 5 o'clock... maybe 4, but no more. My son commented the other day that he learned why I keep the heat set around 5 o'clock. When he used the van he saw how low on the dial the setting was. He moved the dial up into the red. After the engine heated up he got too warm and dialed back to my typical setting. The dial is like a thermostat setting, not a direct signal to the heater valve. When the heating system is working properly, a low position setting on the dial is enough to keep warm in the front seats.

You might try this procedure. It can't hurt.


FWIW.

vic
 
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ECU

Well-known member
One issue could the Aux water pump. A small electric pump that gets water flowing through the heater core faster among other things.
It mounts to the firewall just about center. You can tell if it is working by touching it. You should feel the vibration of it working when the engine is running or you have REST on.
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You might try this procedure. It can't hurt.


FWIW.

vic
I have tried it and no luck, I have a feeling it could be the electric pump I will check it tomorrow. If thats good then I will replace the thermostat. After that, I'll probably come back to this post. Is there a way to check the thermostat is working without taking it out?
 

calbiker

Well-known member
Within 10 minutes of driving, coolant temperature should have reached 170 F.

A datalogger like Dave’s will indicate if the thermostat is functional.
 
I am going to replace the thermostat, valve heater, and pump just for peace of mind. I'll bench test the ones coming off to keep as spares or give away to the community. Will keep everyone updated on the mystery hopefully tomorrow when the parts come in the mail.
 

Patrick of M

2005 T1N 2500 (NA spec)
Fwiw, engine will not get to full temp idling, and will lose full temp idling on a cool day
 
Fwiw, engine will not get to full temp idling, and will lose full temp idling on a cool day
I figured as much, I drove the van a good 15 miles to get it nice and warm and it still wouldn't blow cold at 190*. Just got the replacement parts so I'll be draining the coolant and replacing some parts in hopes that I fix the issue.
 
Quick question since I am putting in these parts and I figure I might as well do a coolant flush. During this flush, I plan on putting in distilled water to flush the old coolant. Then that got me wondering, why not just run the benz with just distilled water? Its much colder, and I dont live in a place where my coolant would freeze over. Any reason this would be a bad idea?
 

Aqua Puttana

Poly - Thread Finder
What Patrick said.

... Any reason this would be a bad idea?
It's a terrible idea. The cooling surfaces are iron, aluminum, with a few brass bits thrown in. The recommended G05 HOAT coolant contains corrosion inhibiters, lubrication for the water pump, anti-cavitation additives, and other design features. There have been reports of people having coolant pump bearing and seal failures after running with water only or other chemicals as a flush procedure. Were the failures related? :idunno:

If the coolant has been changed on the proper schedule a flush may not give much return on investment.

:2cents: vic
 
What Patrick said.


It's a terrible idea. The cooling surfaces are iron, aluminum, with a few brass bits thrown in. The recommended G05 HOAT coolant contains corrosion inhibiters, lubrication for the water pump, anti-cavitation additives, and other design features. There have been reports of people having coolant pump bearing and seal failures after running with water only or other chemicals as a flush procedure. Were the failures related? :idunno:

If the coolant has been changed on the proper schedule a flush may not give much return on investment.

:2cents: vic
I figured and it was just a curious thought. I have the appropriate coolant I will add
 
So just finished installing a heater valve(easy), auxiliary water pump(easier), and the thermostat (what a nightmare). I believe what made the thermostat install such a pain is that the previous owner installed the wrong one? This is the part that came off which is significantly bulkier than the one i put on. Could this be why my heater wasnt working? It says 87* on it.
 

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Aqua Puttana

Poly - Thread Finder
.... Could this be why my heater wasn't working? It says 87* on it.
Possibly, but I doubt it.

90C or 195F is design. 87C = 188F

Both my T1N's put out good heat with the dash gauge around the180F mark. In winter it is sometimes below 180F.

:2cents: vic
 
Ok so I had a chance to get the van up to 190 degrees and still no hot air. I double checked that the heater control is working (goes from 12v to 0v. Blower motor works. Thermostat is new and so is the heater valve and auxiliary pump. Does this mean that my heater core is jamed?
 

Aqua Puttana

Poly - Thread Finder
My recollection is that the heater valve is open when no power. You might use low pressure air to see if the air will flow through the heater core. The reason that I mention the open valve is for possibly easier access vs getting the heater core connection(s) proper available for access. Best would be to apply the low pressure air to the outlet of the heater core. A reverse air flow might help to clear a minor blockage.

vic
 
How big are the passages in the heater core, and how likely is that this obstruction is not letting any heat pass through?

Im trying to wrap my head around understanding and pinpointing my problem. In the picture, the following tubes are hot(colored red) in my scenario.

Also where is this t split? Is it reachable from the outside? Also what if there is a blockage at my espar? (Its old and might be a problem) Would that matter at all?

Lastly which line primarily carries hot coolant to my heater core from the 3 way valve?
 

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Nautamaran

2004 140” HRC 2500 (Crewed)
That Tee is just upstream from the heater valve at the other end of the bypass hose, tucked up under the windshield lip.
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The heater valve is downstream from the cab heater core, and switches between heat return (0v) and the bypass line (+12v). Control is PWM, with about a 1 second frequency? Pulling the connector should give you full heat.
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The Boost Heater is behind the headlamp and is in series with the heater core and the EGR valve cooling jacket. It carries full heater fluid flow regardless of the heat bypass valve’s state. If this flow is blocked nothing moves or get properly cooled... a short length of 3/4” tubing can be used to join the hoses and bypass the Espar heater.

I like Vic’s advice to remove the core hose from the valve and gently blow back the core. Removing both the “heater return“ and “bypass” from the valve and blow into the return hose. It should flow freely from the bypass hose. You should also get free flow back to the block from the valve, and through the EGR/Espar/bypass path.

-dave

Added: our posts overlapped. Your plan looks fine, but go easy on the pressure... the rad cap is rated 20psi so I’d stay near that?
 

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