Honda Pilot - Honda Pilot Forums banner

1 - 20 of 27 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter · #1 ·
2006 EX-L Navi, 216k miles

Symptoms: Engine warms up normally but heater won't blow warm air unless car is moving and gas is slightly pedal depressed. Had to take a phone call in the car yesterday - ran for 45 minutes and cold air is all that came out of the blower. But when I drove home in the evening, warm air was delivered as long as had the accelerator engaged just a bit. Soon as I came to a stop - back to cold air. Also, even on the maximum heat setting, the temperature of the air never gets uncomfortably hot.

I checked the coolant level this morning - exactly at MAX. Could it be the water pump? Is that driven from a power take-off? I'm due to have the timing belt and water pump replaced.
 

·
Registered
Joined
·
2,116 Posts
2006 EX-L Navi, 216k miles

Symptoms: Engine warms up normally but heater won't blow warm air unless car is moving and gas is slightly pedal depressed. Had to take a phone call in the car yesterday - ran for 45 minutes and cold air is all that came out of the blower. But when I drove home in the evening, warm air was delivered as long as had the accelerator engaged just a bit. Soon as I came to a stop - back to cold air. Also, even on the maximum heat setting, the temperature of the air never gets uncomfortably hot.

I checked the coolant level this morning - exactly at MAX. Could it be the water pump? Is that driven from a power take-off? I'm due to have the timing belt and water pump replaced.
Could be the pump, but if the engine doesn't overheat, you might want to first check the coolant level in the radiator, not the overflow tank. (Assuming that's where you're seeing the MAX level) It's also possible there's an obstruction somewhere in the heater circulation circuit that takes additional pressure from the rev'd up water pump to overcome. It could be something as simple as an air bubble that squeezing the heater hoses might help clear up. If not, you might need to flush out the heater core.

When was the coolant last changed and how does it look?
 

·
Registered
Nobili spiritus embiggens pequeño sparus tyre.
Joined
·
9,263 Posts
Do get your timing belt and water pump replaced if they are due.

If your blower is working and you check to make sure your air mix motor is working properly as well, then have a look at the heater control valve, and it may be something as simple as a loose screw there. It's not so easy to find, so here are some pictures and a process that will cost you nothing but a squirt of WD-40 and the turn of a Phillips screwdriver.

Spray WD-40 on the screw, wait overnight if necessary for it to penetrate, then try to tighten that screw. Maybe add a little Loctite if you're feeling spendy. Done.

1. On the cover of the engine find the word "HONDA"

2. From the Letter "H" go straight back to the firewall.

3. Now go down 13.5" from the underside of the firewall.

4. The valve is attached to the firewall by a bracket with the valve being about 3-4 inches away from the firewall. Look for a thin cable coming out of the firewall. This cable attaches to an arm. The arm attaches to the top of the valve with a Phillips screw on the very top.














Even if that wasn't the problem and you do have to flush the heater core, at least you can find comfort and reassurance in confirming that you don't have a screw loose. :)
 

·
Registered
Banned from wife’s 2005 Pilot LX
Joined
·
3,839 Posts
My first two thoughts were the air bubbles in the cooling system or the heater control valve, both already mentioned above.

How is heat in the rear? That has a separate heater core and bypasses the heater control valve at the firewall.
 
  • Like
Reactions: aggrex and plplplpl

·
Registered
Joined
·
9,436 Posts
As others have mentioned, my greatest fear is that you may be having a timing belt water pump issue. When the belt is stretched is rides loose under the pump. When you accelerate it tightens just enough to engage it, pumping warm antifreeze through your heater core.
144633

(Loose stretched timing belt ^)
So..., the million dollar question, When was the timing belt water pump job done last?
 
  • Like
Reactions: plplplpl

·
Registered
Banned from wife’s 2005 Pilot LX
Joined
·
3,839 Posts
Well, OP said the timing belt and water pump service is due so at least this won’t be a $1k+ surprise. And that could fix the problem for free if your hunch is right.
 

·
Registered
Joined
·
9,436 Posts
Well, OP said the timing belt and water pump service is due so at least this won’t be a $1k+ surprise. And that could fix the problem for free if your hunch is right.
Family member was having overheating issues during long periods at idle because of a stretched timing belt and 1 dead cooling fan.
Another symptom of this was hesitation when accelerating from a stop.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #8 ·
Thanks for all replies...

Original timing belt & pump replaced at 115k miles. Original shop that did the work no longer wants to do it - they are primarily a body shop. Had an appointment in August at the shop that did the belt on our PT Cruiser, but then through a comedy of events, have never been able to make that appointment stick. The only local shop I found that was willing to do it wanted more than I was willing to pay - I think I paid $700ish in the past and their estimate came in at just under $1k. I know it was only $300 difference, but just wasn't ready to pay that much at the time.

Going to check the tightness of the screw tomorrow. And then I think I will go ahead and get the belt replaced. Maybe that fixes it.

Appreciate the advice provided.
 

·
Registered
Joined
·
2,960 Posts
Back in 2014 the local dealer had a TB/WP/tensioner/belt special for $850 minus 150 coupon. Today I expect that same TB service might be $1200-1500
 

·
Registered
Joined
·
2,116 Posts
Back in 2014 the local dealer had a TB/WP/tensioner/belt special for $850 minus 150 coupon. Today I expect that same TB service might be $1200-1500
"Back in 2021 getting a timing belt only cost $1200-$1500."
"Dad, get real ... my electric car doesn't even have one of those whatever they are. But I do need a new battery, so can you lend me $12,000?"
 

·
Registered
Joined
·
9,436 Posts
Thanks for all replies...

Original timing belt & pump replaced at 115k miles. Original shop that did the work no longer wants to do it - they are primarily a body shop. Had an appointment in August at the shop that did the belt on our PT Cruiser, but then through a comedy of events, have never been able to make that appointment stick. The only local shop I found that was willing to do it wanted more than I was willing to pay - I think I paid $700ish in the past and their estimate came in at just under $1k. I know it was only $300 difference, but just wasn't ready to pay that much at the time.

Going to check the tightness of the screw tomorrow. And then I think I will go ahead and get the belt replaced. Maybe that fixes it.

Appreciate the advice provided.
I'd never want to discourage someone getting a timing belt when it's due, but know that if a stretched timing belt is causing the water pump not to turn, there should also be an engine overheating problem when idling for an extended period.
 
  • Like
Reactions: pstelter

·
Registered
Joined
·
2,116 Posts
I'd never want to discourage someone getting a timing belt when it's due, but know that if a stretched timing belt is causing the water pump not to turn, there should also be an engine overheating problem when idling for an extended period.
I ruled out wp and a sticking thermostat for the same reason. Hopefully, it's something simple like an air bubble or loose screw, or just low coolant. Sometimes radiator caps will leak or stick off in the vacuum direction and not pull from the reservoir so a "Max" level there doesn't always mean the system is full. It can be down enough to let air into the heater circuit without overheating the engine.
 

·
Registered
Joined
·
9,436 Posts
I ruled out wp and a sticking thermostat for the same reason. Hopefully, it's something simple like an air bubble or loose screw, or just low coolant. Sometimes radiator caps will leak or stick off in the vacuum direction and not pull from the reservoir so a "Max" level there doesn't always mean the system is full. It can be down enough to let air into the heater circuit without overheating the engine.
Inspecting the radiator would be in good order. It is an 06 and might need replacing when doing the timing belt job. Great time to replace all the coolant.
 
  • Like
Reactions: pstelter

·
Registered
Joined
·
9,436 Posts

·
Registered
Nobili spiritus embiggens pequeño sparus tyre.
Joined
·
9,263 Posts
Seems a little low. :)

Fill it and burp it well, then recheck it.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #18 ·
Yeah it was low...and also the expansion tank was NOT full. I'm so stupid - dirty bottle. Anyways filled it - took about half a gallon - and I now get warm air at idle. Saw no evidence of any leaks. I'll go and check again in a bit after its been sitting for a few hours.

So assuming it is NOT leaking out into the air, where then is it going? Is there any sniffer that can test for the presence of coolant in the exhaust?

I should note that this is the 2nd replacement radiator that I have...the OEM unit developed a leak and was replaced by an aftermarket unit. That unit then developed a leak between the coolant and the transmission. Replaced the radiator again and flushed the transmission and it has been fine for almost 10 years now.
 

·
Registered
Joined
·
9,436 Posts
Yeah it was low...and also the expansion tank was NOT full. I'm so stupid - dirty bottle. Anyways filled it - took about half a gallon - and I now get warm air at idle. Saw no evidence of any leaks. I'll go and check again in a bit after its been sitting for a few hours.

So assuming it is NOT leaking out into the air, where then is it going? Is there any sniffer that can test for the presence of coolant in the exhaust?

I should note that this is the 2nd replacement radiator that I have...the OEM unit developed a leak and was replaced by an aftermarket unit. That unit then developed a leak between the coolant and the transmission. Replaced the radiator again and flushed the transmission and it has been fine for almost 10 years now.
I feel better if this fixes your heating issue. I still wouldn't put the timing belt water pump job off to long.
I'd inspect the hoses. It doesn't take much of a leak to cause the disappearance. Replace cap if original. Water can evaporate as steam.
 

·
Registered
Nobili spiritus embiggens pequeño sparus tyre.
Joined
·
9,263 Posts
And burp it well.

 
1 - 20 of 27 Posts
Top