Tim, In your heater core addition to your bumper for enhanced cooling, towards the end of your write up you state the valve is not necessary? That's the control valve on the heater core you speak of? I'm taking on this modification soon, so brace/ plumb it with any heater core that will fit in behind the bumper? Likely junkyarding for the heater core according to size. Thanks- Austin
Initially I thought I'd need a valve to shut off flow (to the added heater core) so the van would warm up faster in cold weather. As it turned out the van warms about the same regardless, so I just leave it open all the time. If I did this mod again I'd probable not take the time to install a valve here. Having it was valuable for testing though. With that valve closed the van is essentially the same (regarding coolant flow) as before. With it closed and driving in conditions that previously led to overheating (up a hill on a hot day with AC running) you could see the temp gauge rising, but as soon as I opened it, the temp would start dropping back down.
When selecting a core, I would look for one designed for a vehicle with a large passenger cabin and a single heater core. The Previa fit that description, but there are others out there. The idea is to get one with a large capacity (more BTU's are better). Tim
I found a heater core and I'm about to install it in my front bumper. I'm just wondering if it's ok to just " T " into the hose on both sides as far as the flow of coolant is concerned? No need for any directional valve?
If you look under the front of the van, you will see 2 heater hoses disappearing into the floor where the heater core is located. Follow them back and identify the one with the shut-off valve on it. You will want to tee off that one behind that valve (towards the rear of the van). The other hose doesn't matter (you can tee off that one anywhere it's convenient). If your van has an AC condenser in the way (like mine did on page 1), then you will likely need to drop the condenser to get access. Tim
I have been looking at refreshing and improving my van's cooling system. I figured a good place to start is with adding a more accurate temperature gauge. I like tim's Koso implementation mentioned above and also the engine watchdog that gunflint posted about. I am not sure I am ready to part with over $100 to get a temp gauge in there so I have been poking around on the internet to see whats out there.
While looking at engine watchdog's on ebay I came across this knock off seeming one for about half the price shipped to the US from Canada. After digging a little deeper i realized that that thing appears to be an STC-1000 temperature controller running custom firmware flashed with an arduino. I was not familiar with the STC-1000 prior to going down this rabbit hole but its popular in the homebrew scene. You can find them being sold under various names on ebay, amazon, and aliexpress for anywhere from around $10 - 20. Cheap! But there are caveats. The obvious being how much you want to tinker with programming and flashing your own firmware (requires a specific version of the STC1000 which is $18). If you don't go down that road and use a stock one there may be issues with the temperature range you are able to pickup. For example, this one on amazon: Docooler will stop reading temperature above 194 degrees F and display 'HHH' on the screen (overheat). But if you get this one it will go up to 120 degrees Celsius before you get the HHH (and reopening the switch for external buzzer or fan relay! keep reading!), which would work great (248F) and its only $11.99, but it only displays in Celsius if you care about that.
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So for $11.99 I could potentially get a decent digital temperature gauge AND a thermostat to wire to my fan relay. It seems like the hayden, derale, flexalite etc. just don't last very long and have accuracy issues for some...unless you spend over $100 for the flexalite one Tim has written about. Perhaps the temperature range issue can be remedied just by connecting a different NTC temperature probe?
I am not sure if you are limited to what you can stick the probe it comes with on or in or if you can some how rig up one to get in the unused ports on the engine to measure the coolant temperature. I would probably go with soldering or epoxying a ring terminal or copper lug onto the probe to use as a washer on some bolt on the head. Seems like engine watchdog owners are happy with that style of measurement.
This person on expo forum uses one to monitor temp and control their fan on their mitsubishi pajero: Pictures and info
In this DIY Engine Watchdog thread a user reports using a $10 ebay controller for 7 years!
Yes I am cheap, keeping the van going is already expensive in a lot of areas. Maybe this is old hat to everyone else and maybe there are other, better options? please share! I have never added any auxiliary gauges to a vehicle so this was all new to me.
Hey all -- Just wanted to quickly share my experience with the 'extra radiator' mod -- I recently did a head gasket and I wanted to protect my investment/never ever try to do that job in an apartment parking space ever again, so I started looking to gather the parts for a timsrv-style heater core extra-coolin' mod on the cheap.
After doing a lot of online browsing, I found this heater core which fit the bill on Amazon. It's compact enough to stuff up behind the bumper, it has 5/8" inlet and outlet (same as our heater hoses), it's designed to heat an SUV (decent BTUs) and best of all, it was cheap and readily available.
I did buy the "extravagant" metal T-connections from Dorman -- they were twice as expensive as the plastic but I figured they'd hold up better in the long run.
After that, it was just a matter of figuring out how to attach -- I used angle aluminum, as tim suggested, and mounted it using an existing, unused 10mm welded nut and a hole through the horn mount -- this places it directly in the center of the grille without any interference (I didn't take a photo of my angle aluminum piece. It's not pretty but it does the job).
Then, it was just a matter of plumbing the hoses:
And good and tucked away!
This mod didn't require removal of the bumper, though it would have made it easier, as i did bang up a couple fins wiggling the thing in and out getting the fit right. Results are immediate. Even scaling the long hill up to my apartment, the temp gauge drops if I've been sitting in traffic. Very excited for summer freeway use/air conditioning! All in all, this was an under-$50 mod that seems entirely worth it, given the availability of parts.
All credit goes to Tim for the original suggestion and road map!!
PS: As I was editing this post, I realized my photo shows a missing hose clamp. I actually had to go to the van and check and make sure it was actually there.
Awesome! Nice job. That looks like it may be a better selection than the Previa core. Very nice the way it fits and it looks as though the nipples come out in exactly the right place. Tim
Hoping to complete this mod during the upcoming week - Can you help me understand where to T into on the line with the shutoff valve?
Looking at this photo - am I looking to T pre (toward the front of the van) the valve I circled here? Am I way off? Thank you!
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Yup, that's right. Situate it before (in this case, towards the back of the van) than the valve that opens and closes the flow to the actual heater core. That way, you'll always be supplying your new core with coolant.
The weather's really started to get warm here and I can confirm this mod is great. I almost always see a little cooling when I've started moving from a stop, which is great piece of mind after dealing with overheating issues for over a year!
Gambit,
What you have circled is one of the a/c ports used for charging the a/c system. Mistakenly cutting into that if there's any pressure in the system could prove dangerous. There's two hoses attached to pipes coming out of the floor just behind the bumper. These are the front heater hoses. One of the hoses has a valve with a plastic sheathed control cable attached to it. The valve is located several inches from where the pipes pass through the floor.
Thanks - Very helpful!Originally Posted by originalkwyjibo
Whoops, I should have looked more closely at that photo! If you look at my pictures, you'll see a piece bolted to the floor of the van -- that's the heater valve. (It's not particularly well photoed, but it will be evident when you're under there. Removing the condensor/fan is the way to access the heater hose routed to that valve. Sorry for any inadvertent confusion!
Got this all hooked up - was easy to spot where to splice into once the AC was lowered.
One question - is there any reason the engine would warm up quicker now that this has been installed? It seemed to get up to temp in about half the time as usual. Which seemed a bit odd...
Otherwise the initial drive seemed all good. Running nice and cool, though this was mostly me trying to be proactive and avoid any future issues. We'll see when it gets a bit warmer out.
IDK, but perhaps you got an air bubble trapped in the engine that only worked it's way out after the t-stat opened. Tim
That could have been it - I topped it off this morning and drove about 45 minutes. Seemed to be back to normal, and never got over 189 in some stop and go traffic. It would drop quickly again down to 180 once I was moving.
I was brought here from another post I created where I didn't do my research.I'm working on doing the aftermarket temp sensor like Tim did. I'm not going to do the alarm but I did order the temp gauge and adapters. Any advice on mounting? I'm feeling a little uneasy about drilling through my pretty dash.
I went through one of the extra swtich blank panel options - I just grabbed an extra from the last junkyard van I scavenged. This way it's easy to go back... though I don't ever see that happening. Only photo of the gauge I currently have on me. See it to the right of the wheel. Was a bit of a battle to get the plug out of the block - but worth it in the end!I was brought here from another post I created where I didn't do my research.
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Last edited by Gambit; 05-30-2018 at 04:05 PM.
Thanks for the idea, I think I will go that route. Have any more pics of that custom cup holder?
Hey - fellow Oakland van owner! Sure, I'll try to remember to grab some more photos of the cup holder in the next day or so - i'll just send them to you so not to muddle up this thread too much...Thanks for the idea, I think I will go that route. Have any more pics of that custom cup holder?
Hey all - working on getting the digital thermometer reading from the 'Extra/Unusued Port' that Tim outlined in the photos above and was just wondering if anyone else had a HECK of a time getting that plug out. I've hit it with PB Blast and let it soak for hours to no avail. Any tips/tricks welcome before i strip this one any further
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