Hey Oppo: Why is my van overheating?

"ttyymmnn" (ttyymmnn)
06/20/2016 at 14:32 • Filed to: None

This started a little more than a week ago (‘03 Odyssey). I was idling with the AC on, and the AC started getting warm and the engine temp started going up very quickly (it’s got a gauge, not a too-late light). Revving the engine, though, brought the temp back to normal, for about 10 minutes. Then it climbed again. When I drove it, it was fine. No overheating. When I stopped at a long light, it started to overheat again.

So, I took it to Honda service, and they could find nothing wrong. It never overheated for them. The service rep drove it in the heat of the day, left it idle, nothing. So I brought it home, drove it, and it was fine for a few days.

But then today, it started again. I left it idle with the AC on for about 5 minutes in a store parking lot, and it got super hot again. But once I revved the engine, it cooled down. Then it heated up at a stop light. When I got home, I left it idle in the driveway, and this time it got hot, so I popped the hood to confirm that both cooling fans were running. They were. The coolant overflow bottle was full, but bubbling.

Any ideas? Is it time for a new radiator? The van is 13 years old, with 150k miles on it.

DISCUSSION (82)

Nibbles > ttyymmnn
06/20/2016 at 14:37

I’d say, given your data, that there’s either a clog forming somewhere creating a bit of a bottleneck, or your water pump is starting to go (necessitating the revs to keep coolant flowing well).

Jcarr > ttyymmnn
06/20/2016 at 14:38

Partially stuck thermostat that is getting forced open enough when the engine is revved?

ttyymmnn > Nibbles
06/20/2016 at 14:40

Service guy said water pump was okay. I’m just confused by the intermittent nature of the problem.

ADabOfOppo; Gone Plaid (Instructables Can Be Confusable) > ttyymmnn
06/20/2016 at 14:40

It’s going through minivan-menopause. Be prepared for random angry warning lights to appear without any previous symptoms and then suddenly disappear.

Or, I’m full of shit and take video of it overheating and take back to the Honda dealer?

TheHondaBro > Nibbles
06/20/2016 at 14:40

That's what I was thinking. Revving the engine would get the pump going, but at normal revs the alternator can't supply enough power to the pump to keep it going.

Saracen > ttyymmnn
06/20/2016 at 14:40

Probably because it’s hotter than the surface of the sun outside (at least it is where I’m at)

ttyymmnn > Jcarr
06/20/2016 at 14:40

But would that be an intermittent issue? That’s what’s confusing me.

Berang > ttyymmnn
06/20/2016 at 14:41

Coolant levels are low? Has the system been flushed in the past year? Usually if the temp surges it means there’s air or something stuck in the system, when you rev it forces water past it. If you hear any glugging sounds with the heater on that’s another hint.

ttyymmnn > Saracen
06/20/2016 at 14:41

Well, there is that, but it’s been hot here before. This baby has been through 12 summers and a drive through the desert southwest. No problems ever until now.

ChooChooMotherFudger > ttyymmnn
06/20/2016 at 14:42

Is it an electronic fan?
If so is the fan going when it is over heating?

ttyymmnn > Berang
06/20/2016 at 14:42

I asked the service guy if flushing and refilling the system would help, and he said it wouldn’t. But I’m not convinced. The overflow bottle is full. I never filled it. That suggests to me that the coolant isn’t making it all the way through the radiator.

jariten1781 > ttyymmnn
06/20/2016 at 14:42

Hrmm, I’d guess an intermittent connection on the fans or, if there’s a sensor that kicks on the second fan, that starting to go. If that doesn't check I'd probably flush the rad and see how flow is. If that doesn't show anything I'd pray that I had a water pump that wasn't under the timing belt cover...

ttyymmnn > ChooChooMotherFudger
06/20/2016 at 14:42

Two, two-speed fans. Both were running when it was overheating.

Jcarr > ttyymmnn
06/20/2016 at 14:43

I couldn’t say. Just seems to me like the logical issue is some sort of interruption in coolant circulation. Beyond that, I’m just guessing, unfortunately.

LongbowMkII > TheHondaBro
06/20/2016 at 14:43

I figured it'd have a belt driven pump?

Steve in Manhattan > ttyymmnn
06/20/2016 at 14:43

Thermostat, or cracked housing? Cheapest fix first, after all ....

TheHondaBro > ttyymmnn
06/20/2016 at 14:43

They might be trying to get you in when it’s a much more expensive problem, but that’s just the cynic in me.

If it's not the pump, then it might be a wiring issue or even your alternator. Is it just the temperature that you're seeing problems with? Is your car cranking slowly?

ttyymmnn > ADabOfOppo; Gone Plaid (Instructables Can Be Confusable)
06/20/2016 at 14:44

Interestingly, the SRS warning light came on two days ago and just turned off on its own.

SidewaysOnDirt still misses Bowie > ttyymmnn
06/20/2016 at 14:44

The faster your engine revs, the more water pressure there is behind it. Thermostat could be jammed but being forced open once in traffic.

ttyymmnn > Steve in Manhattan
06/20/2016 at 14:44

Best to start cheaply.

ttyymmnn > TheHondaBro
06/20/2016 at 14:45

Everything else seems to be working just fine. Engine runs well, AC is cold, idles well, starts easy (got a new batt a few months ago).

Nibbles > LongbowMkII
06/20/2016 at 14:46

I figured that as well. I’m not all up-to-date on these new electric-driven pumps and such. I know nothing about the 2003 Oddyssee but I have seen some really weird coolant flow problems in my life

SidewaysOnDirt still misses Bowie > ttyymmnn
06/20/2016 at 14:46

Lol, Takata.

ttyymmnn > SidewaysOnDirt still misses Bowie
06/20/2016 at 14:46

That makes about as much sense as anything. It seems to me that if the radiator were clogged, or not circulating completely, the problem would not be intermittent but constant.

OPPOsaurus WRX > ttyymmnn
06/20/2016 at 14:47

its overheating because its getting too hot.

ttyymmnn > SidewaysOnDirt still misses Bowie
06/20/2016 at 14:47

It’s been recalled twice for the SRS. Theoretically, it’s all good. But Takata.

ttyymmnn > OPPOsaurus WRX
06/20/2016 at 14:47

Thanks. How much do I owe you?

smobgirl > ttyymmnn
06/20/2016 at 14:47

That used to happen all the time in my Civic. Could just be an unrelated Honda Gremlin.

Steve in Manhattan > ttyymmnn
06/20/2016 at 14:48

Indeed - I’d say rebuilding the transmission is the last thing you do. Right after rotating the tires and putting in a new fuel pump.

PartyPooper2012 > ttyymmnn
06/20/2016 at 14:48

Second that motion. If you have chunks of crap in your coolant, it might cause your thermostat to be stuck at times.

A) replace your thermostat. It’s like 10 bucks and really easy to replace

B) flush your coolant system

For shits and giggles, make sure the flushed fluids is collected into a reservoir that you can inspect - check for anything thats not liquidy liquid - like chunks of rust or rubber from hoses.

OPPOsaurus WRX > ttyymmnn
06/20/2016 at 14:48

tree fiddy should do. I have some purchases to make

ttyymmnn > smobgirl
06/20/2016 at 14:48

That’s not encouraging. This van has been, for the most part, rock solid all these years.

ttyymmnn > Steve in Manhattan
06/20/2016 at 14:49

Should I get it powder coated while I’m at it?

PartyPooper2012 > Jcarr
06/20/2016 at 14:49

yeah. i second that thought process. thermostat either malfunctioning or getting stuck closed when it should be open via some dirt in coolant

PartyPooper2012 > Nibbles
06/20/2016 at 14:50

Yeah. I would start with thermostat and coolant flush. if that didnt fix it, water pump.

ttyymmnn > OPPOsaurus WRX
06/20/2016 at 14:51

You mean a boat payment to make? Oh wait, that’s my kid’s orthodontist. Seriously, he’s got trophy fish hanging in his office. He wanted to put my son through a second course of braces, after the first course made his teeth really pretty. I said, ah, thanks, but no thanks.

PartyPooper2012 > ttyymmnn
06/20/2016 at 14:51

you havent powercoated your diesel fuel yet??? What are you waiting for?

Jcarr > ttyymmnn
06/20/2016 at 14:52

Based on your initial description, the issue seems to present at idle engine speeds (low pressure) and alleviate at varied or increased throttle (higher pressure). Could just be enough of a stick or clog that idle pressure isn’t enough to push it open.

TwoAprilFools > ttyymmnn
06/20/2016 at 14:52

When was the last time you replaced the radiator cap? It could be not holding in pressure.

OPPOsaurus WRX > ttyymmnn
06/20/2016 at 14:52

yea... i’m pretty sure i chose the wrong profession.

Dave the car guy , still here > Steve in Manhattan
06/20/2016 at 14:52

Then maybe look at water pump?

ttyymmnn > OPPOsaurus WRX
06/20/2016 at 14:54

I know I did.

ttyymmnn > TwoAprilFools
06/20/2016 at 14:55

Never replaced the cap. It’s original. But, if the cap weren’t sealing, wouldn’t that lead to a loss of coolant?

ttyymmnn > Jcarr
06/20/2016 at 14:55

You mean inside the radiator?

ttyymmnn > PartyPooper2012
06/20/2016 at 14:56

I’ve been saving up for a new turbo encabulator.

EL_ULY > ttyymmnn
06/20/2016 at 14:56

First I though water pump because of the revving bit....

...then you mentioning bubbling.... that is not good. It’s a closed system yo. There shouldn’t be bubbles. Bubbles mean you blew the head gasket :(

CalzoneGolem > ttyymmnn
06/20/2016 at 14:57

Oh come on you know you love to toot your own horn.

PartyPooper2012 > ttyymmnn
06/20/2016 at 14:57

cool. make sure to get a tattoo of it on your arm.

Jcarr > ttyymmnn
06/20/2016 at 14:57

Wherever the thermostat is housed. If it’s not opening at the temp it should, that would restrict flow and cause an overheat.

ttyymmnn > EL_ULY
06/20/2016 at 14:57

But I don’t think it ever got hot enough for that, or at least not hot enough long enough.

ChooChooMotherFudger > ttyymmnn
06/20/2016 at 14:58

Well the things needed for cooling are airflow (movement or fan, check), surface area (not overheating when moving so rad is probably fine, check), and coolant flow (don’t know).

That is my logical way of looking at it, but sometimes working on cars is anything but logical.

ttyymmnn > ChooChooMotherFudger
06/20/2016 at 14:59

Yeah, I get all that and it makes perfect sense. What doesn’t make sense is the intermittent nature of it.

OPPOsaurus WRX > CalzoneGolem
06/20/2016 at 15:01

i’ve been tootin’ my own horn all day long. i’ve been asked if i’m going to do that, to go somewhere where no one else can smell it.

nafsucof > TheHondaBro
06/20/2016 at 15:04

Water pump is driver by the alternator belt not 12v.

Invinciblejets > ttyymmnn
06/20/2016 at 15:06

Start by flushing and purging the system.

smobgirl > ttyymmnn
06/20/2016 at 15:14

Well, that was the ONLY electrical gremlin the civic had in 15 years/210K miles. I never solved it. I would assume nothing drastic has gone wrong since because my neighbor still drives it.

I did have a stuck thermostat at one point too, but the shop that was supposed to diagnose my sporadic overheating blew the head gasket instead.

nerd_racing > EL_ULY
06/20/2016 at 15:15

this, the gasket could have perforated, allowing compression into the coolant system. I would work on fixing that before something else blows up (I.E. head warps and destroys cam, locks up, and engine impacts internally.)

nerd_racing > OPPOsaurus WRX
06/20/2016 at 15:16

Kinja'd!!!

Steve in Manhattan > ttyymmnn
06/20/2016 at 15:18

Before the powder coating, you should get those floormats that hold a lot of water, put sheepskins on all the seats, and rotate the tires back to where they were.

crowmolly > ttyymmnn
06/20/2016 at 15:21

I am thinking water pump.

I know you said you had it checked, but I had the exact same issue once. On the gas/moving the car was cool, but when I came to a stop or idled the temp shot up very high. I did a pressure test followed by a new thermo and then a radiator flush. None of that solved it. So I yanked the water pump and a replacement fixed the issue. The old water pump was moving coolant but nowhere near enough.

ChooChooMotherFudger > ttyymmnn
06/20/2016 at 15:21

Well something isn’t get enough power (mechanical or electrical) when idling I guess to move coolant.

I would bet some electrical issue. I have had those be intermittent for no good reason more times then I can count.

Steve in Manhattan > Dave the car guy , still here
06/20/2016 at 15:24

Some of the fins possibly came off, yeah - probably the next best fix. Can’t remember if the thing is buried in this or not. Be thankful it’s not a V6 Camry - that’s a lot of hours to replace.

EL_ULY > ttyymmnn
06/20/2016 at 15:30

Aluminum heads, it doesn’t take much. Bubbles = compression gases entering cooling system.

just-a-scratch > ttyymmnn
06/20/2016 at 15:37

I’m not sure how your overflow tank is plumbed, but bubbling sounds odd at best.
The first thing I though of with an intermittent cooling issue was a thermostat that’s sticking shut sometimes. Then again, by your description, revving the engine seems to help solve the problem. That could be a water pump problem.
Have you been losing any coolant? Have you checked for leaks?

A leak could cause a bubbling issue, or result in a vapor locked section of the cooling system, depending on how it’s plumbed of course.

As for the potential head gasket issue, what does your exhaust look and smell like? If it’s more white than normal or has that coolant smell, you could have a head gasket problem.

ttyymmnn > just-a-scratch
06/20/2016 at 15:49

Exhaust is fine, head gasket was checked a couple months ago, but this was prior to overheating problems.

ttyymmnn > EL_ULY
06/20/2016 at 15:50

If it needs a head gasket, I'm getting a replacement engine. Seriously, I investigated the HG as an oil leak issue a few months ago, and it's wicked crazy expensive to fix. It's more cost effective to put in a low mileage replacement.

ttyymmnn > smobgirl
06/20/2016 at 15:52

You're the second person who said something about a head gasket. I'd replace the engine before replacing the head gasket.

iSureWilll > ttyymmnn
06/20/2016 at 16:07

I would highly doubt a water pump or head gasket problem. If the water pump was going, revving it up would be it worse. If it was a head gasket problem you would most likely have more issues than just this one. If you really want to be sure, ask the service guys to pressure test the cooling system. They should have a tester that screws onto where the radiator cap goes to test it.

My guess would be the thermostat is stuck. When you’re at idle, there isn’t enough coolant flow to keep the engine cold (the thermostat is stuck mostly closed). When you rev the engine up, the water pump spins faster and forces the coolant through the small opening in the thermostat and has enough flow to keep it cool.

I’ve had a similar issue on my old BMW before. :) Also, changing the thermostat should cost no more than $30 parts included if you do the labor. At a shop, figure roughly $150-$200 including all labor, parts, fees, etc.

Juan Tawn > ttyymmnn
06/20/2016 at 16:22

Too much Nelly?

Sorry I can’t help :-(

smobgirl > ttyymmnn
06/20/2016 at 16:35

Yeah, not a bad plan. There were special circumstances associated with mine since the shop drastically exacerbated the problem (whether it actually started with a stuck thermostat or not).

ttyymmnn > smobgirl
06/20/2016 at 16:46

I was concerned a while ago that I had a leaking head gasket, but in reality, I had a porous block. First time I’d heard of that. In consolation with the Honda service rep, we decided that a low-mileage engine would be better than trying to repair the HG. However, I may rethink this whole proposition if the engine is toast. It might be time to find a replacement vehicle.

ttyymmnn > Juan Tawn
06/20/2016 at 16:46

Sorry, but I don’t get the reference.

ttyymmnn > iSureWilll
06/20/2016 at 16:48

Thanks. This explanation is the best one I have heard that would explain both the overheating and the intermittent nature of the problem.

brianbrannon > ttyymmnn
06/20/2016 at 18:21

Did you check for coolant in the radiator?

ttyymmnn > brianbrannon
06/20/2016 at 18:47

Yup. The overflow bottle is full, not that I filled it. It makes me wonder if the coolant is not fully circulating through the radiator.

Nimbus The Legend - Riding on air like a cloud > ttyymmnn
06/20/2016 at 19:25

1)Most likely is air in your radiator fluid system

2) could be a bad temp sensor or a sticking thermostat thats not fully gone yet, but on its way out

3) check your radiator fluid for milky residue or milky fluid, and then check under your oil cap for milky oil...

ttyymmnn > Nimbus The Legend - Riding on air like a cloud
06/20/2016 at 19:47

Dipstick and radiator cap look good. I think I’m going to start with a new radiator cap and see what happens. If that doesn’t help, then I’m going to have the coolant flushed, filled and bled and the thermostat changed. I’m fairly certain the water pump is good. I want to try everything before putting in a new radiator.

Nimbus The Legend - Riding on air like a cloud > ttyymmnn
06/20/2016 at 20:04

dont forget to burp your coolant system

ttyymmnn > Nimbus The Legend - Riding on air like a cloud
06/20/2016 at 20:23

How?

Nimbus The Legend - Riding on air like a cloud > ttyymmnn
06/20/2016 at 21:01

you have to run the car for a while, with the radiator cap off.

they sell a special funnel for this job, should be fairly cheap...

depending on the mechanic you as, some will like to have the car face up hill or down hill, Im more from the uphill school, but you should be fine on flat land too

Wagon, semi manual, not brown, turbo because volvo > ttyymmnn
06/20/2016 at 23:29

First make sure the electric puller fans are working and that air is flowing through the radiator vanes at idle. Then burp the system with heat on full and fan on full no ac. If the problem persists , check the thermostat function and then pressure test the system. If the system holds pressure replace radiator cap and check system flow to verify function of water pump.

brianbrannon > ttyymmnn
06/21/2016 at 20:22

The overflow bottle is not the radiator, to check the radiator you have to remove the radiator cap