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View Full Version : Overheating in the TX Summer (no mods) should I worry?



vondervanfan
06-20-2020, 06:00 PM
Hey wonderful van pros -

I've been troubleshooting cooling system issues in my van for about a year now, since she overheated in the West TX heat last year on her way to Santa Fe. The short of it is: got a new thermostat done in nowhere, TX, but she kept overheating 10 miles outside of nowhere-town. Air bubbles kept getting into the system, and once they were cleared, she would run well for 300-400 miles at a time and then get hot. We stopped to cool her down and drove at night to get to NM, clearing the system with the funnel method every time and finding more bubbles to purge. During this time, she did not get into the red and I was very conscious of her well being. Turns out the guys at the first repair shop had not tested her radiator cap and also did not thoroughly hook up the lower radiator arm to the thermo housing after the work... :swear:

My mechanic in Santa Fe looked at her, confirmed that there was no combustibles sneaking into her coolant, tightened the lower radiator hose which the guys in nowhere, TX had failed to reattach fully, changed her radiator cap and we were good to go. She pressure tested properly and I then drove her over mountains and in the city for a few weeks with no issues.

Well.... 300 miles outside of Austin TX on the road home, she starts overheating VERY suddenly again - at night. Torn the upper radiator arm - ugh - probably because of the time with the bum radiator cap and just general age/weakness. Got an ill-fitting replacement on her and limped back into town bit by bit.

I got the correct hoses once back home and with my own garage and changed her coolant hoses properly, which I realize I should have done before going on the road.... I'm so sorry, Van Lovers, I also learned my lesson about traveling with my own tools....

January/February she was doing great on highway and in the city - then all of the sudden she got to 3/4 hot on the temp gage after a short (20 minute) trip on the highway at 60-70 mph, at night. Sometimes I'd turn her on and she'd cruise in the city, then later she'd creep up and get too hot. Decided to replace the tstat since I don't really trust that mechanic from nowhere, TX to have done it properly/wonder if I hadn't broken the little thing at some point during this saga... OEM spec - I followed llamavan's precise instructions (https://www.toyotavantech.com/forum/content.php?199-Replacing-your-van-s-thermostat) exactly :thmbup:

So my question - this seems like a series of coolant issues, with perhaps an underlying cause that I have not yet located, yes? I'm wondering if she's not got some corroded parts/a pretty substantial blockage somewhere. I'm running distilled water in her now, and it's getting up to 110+ degrees in TX. She'll do great on the highway, but then if I turn the A/C on for long or get into stop-start traffic, she'll start getting too hot, and we pull off and think about our lives for a while. Am I too sensitive because of our past trauma? Could it be that I just should run her with the heat blasting and be gentle in this TX summer...? She doesn't like hills very much, but she can make short trips in the city without issue. The other clue is that once she starts getting hot (god forbid, we turn on the A/C or have a couple steep hills) she does not show that she can cool herself down any longer. She'll maintain at 3/4 of the temp gage for a little while, but then just keep creeping until I turn her off and cool her down...

She's gotten so hot that our overflow tank boils over (proof that the pressure in the system holds, I guess... - I also have pressure tested her since the work I've done). The water that comes out is really rusty-colored, even though I garden hose-flushed her a few times and water was running clear.

Thoughts? Recommendations? Reproachful disapprobations..?

I am reading carefully timsrv's how-to (https://www.toyotavantech.com/forum/showthread.php?1242-Article-Cleaning-the-Throttle-Body&highlight=throttle+body) on adding more sensitive temp gages for coolant temperature, as well as hoping to mod her with an additional heater core or extra help in cooling the system. I don't know if she might be just fine for the moment, and TX heat is just not her favorite - that would be fair - but before the West TX to NM trip, she did not overheat in the 6 months that I had had her. However, I also did not do a ton of summer driving... so it's hard to say.

vondervanfan
06-20-2020, 06:05 PM
Oh and one more quick note - I will be cleaning her throttle body and replacing the TPS (per instructions (https://www.toyotavantech.com/forum/showthread.php?1242-Article-Cleaning-the-Throttle-Body&highlight=throttle+body)), since I realize this sometimes can affect a vondervan's ability to cool itself - though any enlightenment on how exactly the throttle body affects the cooling beyond air flow control, I would welcome. She's always had a rough idle as long as I've had her, though it comes and goes.

Any other fixes of this nature that may help her cool to the best of her abilities?

JPERL
06-20-2020, 07:09 PM
If it stays cool at high speed and overheats at low speed you probably need a fan clutch. Also is the fan shroud in place? If the fan shroud is missing the van will overheat as the shroud directs the air to the radiator

trestlehed
06-22-2020, 03:32 PM
Way back when I bought my van, the radiator was in bad shape. I had it "re-cored" which turned out to be either a scam job or an extremely poorly done job. My van ultimately required a HG job, new stock thermostat, hoses (including hose of death), and a custom 4 row radiator from Ability Radiators in Yuba City, CA. Also Jeggs dual electric cooling fans with a custom radiator shroud.

I'm not suggesting you need to do all that, but I suspect that you have a bad radiator. That's where you should start your troubleshooting campaign.

Here are some helpful threads if you haven't read them yet:
http://www.toyotavantech.com/forum/showthread.php?2759-Cooling-system-Mods&p=16143#post16143

http://www.toyotavantech.com/forum/showthread.php?491-Electric-fans-and-thermostats

vondervanfan
07-21-2020, 02:56 PM
If it stays cool at high speed and overheats at low speed you probably need a fan clutch. Also is the fan shroud in place? If the fan shroud is missing the van will overheat as the shroud directs the air to the radiator

- Thank you! Good reminder on the fan clutch... Any hints on how I might test it? I've been told to pull at and make sure there's play... and there seems to be. I suppose we might as well do that to rule it out. Luckily, the original fan shroud is in place and there are no cracks/chunks missing :thmbup:





Way back when I bought my van, the radiator was in bad shape. I had it "re-cored" which turned out to be either a scam job or an extremely poorly done job. My van ultimately required a HG job, new stock thermostat, hoses (including hose of death), and a custom 4 row radiator from Ability Radiators in Yuba City, CA. Also Jeggs dual electric cooling fans with a custom radiator shroud.

I'm not suggesting you need to do all that, but I suspect that you have a bad radiator. That's where you should start your troubleshooting campaign.

Here are some helpful threads if you haven't read them yet:
http://www.toyotavantech.com/forum/showthread.php?2759-Cooling-system-Mods&p=16143#post16143

http://www.toyotavantech.com/forum/showthread.php?491-Electric-fans-and-thermostats

Thank you for the threads! Since we don't have a mechanic eager to work on her down here, I'm trying to exhaust my drive-way mechanic skills before getting help with a full radiator swap. I haven't gotten to the hose of death yet, but there are no leaks so I'm hoping it can be avoided for now... even with all the helpful posts I am not confident I've located the darn thing...

I truly hope I don't end up with the HG.... praying to the van gods.

Out of curiosity, is your custom radiator a bit more powerful for cooling than the original radiator or did you go that route because they're so hard to find in good condition? We don't use the van to tow, but she does make some long trips sometimes and gets filled up with furniture when friends move. I thought about some modifications that might be available to help her keep cool and if a custom radiator would be worth it - I'd be curious to hear!

Thank you both so much for thoughts and recs!

trestlehed
07-23-2020, 02:01 PM
Out of curiosity, is your custom radiator a bit more powerful for cooling than the original radiator or did you go that route because they're so hard to find in good condition?

Yes to both questions. When I decided to address all the mechanical issues my van had, I also decided that I wasn't going to
half-ass anything.

These vans seem to have a very sensitive cooling system. If just one component goes bad it can be catastrophic to the engine. For example: the aftermarket replacement head gasket is missing some water-jacket passages which restricts the flow of coolant. The Toyota OEM thermostat is recommended over the after-market ones due to the specific "jiggle valve". So if you make an uneducated decision to strictly buy aftermarket parts just to save money, you might end up spending even more money in the long run. The above examples illustrate why this website is so crucial to keeping these vans alive.