Coolant level sensor woes and the traffic hell-hole we call Lima

[Tom Powell]

[Selsk]

Saw this video recently on another thread...

https://youtu.be/RT8Ew43mNg4

I went and tested mine, and then promptly ordered a new cap!

[IdahoDoug]

Mine blew out the threads on the top of a mountain in Montana. We used some plastic scraps and a prescription bottle and some Saran Wrap or something to get off the mountain. Then one of those rubber boat plugs with the brass lever from a hardware store to plug the tank much better and get us to dinner and a place to park and sleep for the night. I also had JB Weld epoxy on board in the kit, and reassembled the sensor at dinner on our table. By the time we left a couple hours later it had hardened enough it would not flow. I tucked it on top of the engine so when we drove away it was warming until we found a place to park and sleep out in the woods. Before we went to sleep, I retrieved it from the mostly cooled engine so it stayed warm inside with us.

The expanding rubber plug (available all over the world) hardly let even a seep escape. So rather than disturb it, we drove 150 miles home with it in place and the epoxy fully cured on the plug as a backup.

Now I keep that nonfunctioning epoxied plug in the glove box for some future hapless Vanagon owner I'll doubtless find beside the road. It won't be Dave, though!!

I don't understand why so many of these blue caps appear to not be working. I bought two in quick succession that had the nipple pointed the wrong way and it turned out an entire huge batch have that. WHen tight, the overflow nipple points 180 degrees away from the overflow tank so you need to put a long enough hose to get it over there.

I have to think those caps and their relief valve are the issue.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[blackglasspirate]

Well it's true that it's a little risky to drive one of these to countries like this where parts can be hard to find, but that's part of the fun, right? And believe me, I DO carry a ton of spare parts - I probably have twice my body weight in spare parts in here. I also did have a spare of this sensor, but then my spare blew out as well so...

When I put in the spare I asked a mechanic in Cuenca where I could find another one or two as backup. His answer..."Hmmmm, maybe Lima?" Ironic that the spare blew out as soon as I got here.

I actually met one of the guys from Fire Wheels last night. A friend and I were walking along the street and noticed an awesome VW LT40 parked on the road with Peru plates. We left a note and later last night the guy came over and chatted with us. He's supposed to come back tonight to hang again and I need to ask him some more questions. Now that I think about it, I've seen that post on Landcruising Adventure, but forgot it was here in Lima.

Today I'm heading to one or two VW mechanics to see if I can get the part from them. Then I'll need to flush the coolant system and refill will something more readily available like the typical green stuff they've got down here. I already contacted one place that said they don't have it, but someone has to. Again, worst case scenario I wait another week for the part from the States to get here - I just want to have a couple extra spares just in case.

As far as the overtightening - you're probably right. I've had problems in the past where the o-ring on the sensor doesn't seem to fully seal and leaks just a tiny bit. The only way I got it to seal was tightening it more and putting some teflon tape on the threads. However, before this blew out the second time, I got a slightly thicker o-ring from a parts store that sealed great, but maybe I still overtightened it.

And Mike is right - you meet the most interesting people and have the craziest experiences out here. We've given plenty of old ladies rides through the mountains who still try to offer us money when we drop them off, and had our adrenaline rushing experience in Colombia transporting a bloodied moto accident victim to the hospital. I think I took another few years off my like and the van's suspension with that one!
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[blackglasspirate]

[tencentlife]

I saw that video awhile ago. Although it's somewhat helpful, the confident sign-off on the new blue cap is premature. Those checks do show that the black one is NFG since it's pressure releasing valve is wide open. The mouth checks the fellow did do not show that the new blue one is in fact good, only that the return valve isn't wide open (the kazoo sound), and that the pressure releasing valve holds tight enough that he can't suck thru it. Since a human can only pull about 6-10"Hg. suction by mouth, all the fellow definitively shows is that that cap will contain at least ~3-5# of system pressure.

A high percentage of these various branded caps are bad when new, and the reason they're bad is almost always because they release at a pressure less than the specification of 1bar (14.5psi). The coolant system at normal temp will run at about 10psi, with normal excursions to higher temp and pressure under higher load, which is why it's routine to see some coolant expelled to the reserve tank, since this is a "no-headroom" system. I remarked in a recent thread that coolant in the cylinder heads will spot-boil actively at idle at system pressures at least as high as 6psi. The system needs the full containment pressure to be fully effective at absorbing heat from the engine top end, and a spot-boiling condition will actually read lower on the temp gauge since the gauge senses coolant temp, not engine temp, and when spot-boiling is occurring, the coolant is absorbing less heat, while not thoroughly cooling the heads.

I only use the Blau brand caps, they have the fewest failures in my experience, and I still reject about 1 in 8 or so for failure to hold the spec pressure. I have yet to see a new cap with a bad return valve, it can of course happen but it's relatively rare.

So do the checks in the cute little video, if your mouth is all the test equipment you have, but be aware that sucking on the outlet only tells you the cap will hold some pressure, but you don't yet know if it holds enough. You would want to keep an eye on things to be sure it isn't releasing coolant in light use and at normal temps, so monitor coolant levels for awhile before being satisfied that new cap is doing its job.
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[Wildthings]

[Jake de Villiers]

[blackglasspirate]

Great advice and explanation as always, Chris. Thanks! I'll keep that in mind when testing the cap.

And thanks Wildthings for the tip on the silicone. I'll grab some from one of the many hole-in-the-wall parts stores around here.

I just got really lucky and was able to source the sensor, cap, AND the tank. Not even sure if I needed a new tank but I figured it can't hurt, especially if my threads might be warped. The VW dealership close by didn't have the part but directed me to a tiny shop a mile or so away. I went there and he had everything I needed. I got two sensors just in case and the prices were about what I would find in the States so not bad. A little less than $40 for two sensors, cap, and tank. Unfortunately the sensor is the newer type (90-91 years) so the connector is slightly different. I'll have to put a new connector on there or modify the existing one just a bit. I also have the one my friend ordered coming from gowesty, so I can always put one of these ones in for now in order to get around for the next week and then swap it with the correct one.

Now I just have to get my hands on some coolant. I had Zerex G-05 in there but pretty much all I can find here is the green stuff. I will need to flush it with water before filling it. Also, I haven't seen any of the green stuff yet that specifically says it is phosphate free, so I'll need to do some digging. Either way, it looks like I won't be stuck in Lima for another week. Woohoo!
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[Wildthings]

In the US all the extended life coolant seems to be phosphate free. Haven't a clue about elsewhere.

[dobryan]

Yep. I use the green stuff and it is phosphate free. Not sure about Lima....
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

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[blackglasspirate]

The stuff I found is labeled "radiator fluid" brand is vistony. On the manufacturer site it says nothing of phosphates, but does say it prevents the corrosion of aluminum. They also have a product that's in a red bottle labeled antifreeze that says it's phosphate free, though I haven't found it for sale yet. Not sure if the actual color of the liquid is red or green. Still got some walking around to do.
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[blackglasspirate]

Just swapped the tank/cap and replaced the sensor. Even though the connector on the sensor is different I can still get the original connector to fit by pulling back the rubber a bit.

I did the blow test on my original cap (Blau brand) and it passed the two blow tests. The cap that came with the replacement tank didn't not and I can blow/suck in both directions pretty easily (I feel kind of dirty for saying that). I may guessing that means the replacement I should bad. Oh well, I have another cap coming from GoWesty anyway.

I got a quote from my friend's mechanic for flushing/refilling the coolant and it's only $17 so I'll probably have them do it instead of trying to do it myself in this nice beachfront neighborhood I'm parked in. Heading there tomorrow to figure it out.
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[Wildthings]

[Wildthings]

Double post, delete

[blackglasspirate]

Well we got back on the road Sunday and have been roaming the dunes of Paracas NP ever since. I ended up going to a mechanic to get the coolant flushed/replaced, but it would have just been better to do it myself in an alley somewhere. The whole ordeal started with another 2 hours in traffic and hitting a taxi. Thankfully those GoWesty steel bumpers are much thicker steel than these cabbies, so I got off without a scratch.

Anyway, the guy ended up putting Prestone Dexcool in it, which is fine I guess other than I'm sure it's going to be harder to find in the event something goes wrong again. Oh well, I can always flush it out a second time and fill it with the green stuff. Unfortunately the guy left a ton of air in the system, so I've been bleeding it out more and more over the last few days. Not a big deal, I guess, but it just goes to show that sometimes you've gotta do things yourself.

Funny thing is, my friend's wife got back to Peru the other day with the suitcase full of parts, including my cap and sensor. They searched it after it was checked in and with all the parts in there (clutch kit, sensors, etc.), what did they take? Just the coolant cap. Either it poses a security threat or someone in airport security is having coolant issues with their Vanagon.

Anyway, all is well now and heading to Nazca this morning. Thanks everyone for your input.
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[blackglasspirate]

A little update on this: I think the new cap that came with the tank (and "failed" the simple blow test) may actually be bad. I think that might also be why it was so hard to bleed the system, because the system wasn't holding pressure. The past two days after stopping after a long grade there has been coolant bubbling out of the expansion tank and the system makes a boiling sound - though I'm not sure if it's actually boiling or just bubbling. When this happens my temp needle is at a normal level, right in the middle or sometimes just a little above. While the vehicle is running there's no leaking, though the level in the expansion tank rises significantly. I'm gonna put my old cap back on there and hope that it fixes it and the sensor doesn't blow out again. Driving up to 4200 meters today and the I stay doesn't give me a lot of confidence!
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'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee

[Wildthings]

Continuous bubbles on an engine at normal temperature could be signs of a compression leak. Not good. I know of no easy fix for this if that is what is happening.

[SyncroChrick]

Hi

i am heading down to Lima tomorrow from San Francisco if you need anything. I have some parts here at home. I plan to go see the start of the Dakar rally.

[blackglasspirate]