AAZ overheat?

[Gizmoman]

I now have about 200 miles on the rebuild. I had a loose hose clamp on the new silicone heater hose going to the hater valve under the dash. When I got home,I noticed water dripping from the passenger door opening and soggy carpet. I checked the overflow tank and it was empty - the pressure tank was completely full though. I'ts all fine now but as it's a hard to bleed Vanagon, I re-checked for air bubbles using the libby-bong method. For some reason, the water temps are getting into the 200+ range and it has me quite worried.

The details are:
New 185* thermostat
Temps are 175-185 tooling around town
Freeway driving at 65 (3200 RPM 7-8 lbs of boost) gets temps to 200 pretty rapidly. As soon as I exit, temps come back to 180 fairly quickly.
The radiator is brand new and the fan was coming on a few days ago but I haven't heard it recently. Even if it was the fan not turning on, I would think freeway speeds and ambient temps in the high 40's would keep it cool - just makes no sense.
I have new SS pipes under the van.
I made a restrictor disc (with a 1/4" hole in the center) which I installed in the upper hose to the pressure tank.
The water in the tank swirls around quite a bit when I rev the engine - not sure if this is normal or not. Hopefully, I don't have a blown HG.
Head studs are ARP torqued to 125 ft/lbs (as per instructions). I have not re-torqued them.

This is really upsetting after all the work I've done. From what I have read, the cooling system is quite adequate for this engine - something just isn't adding up. Maybe I have the hoses to the radiator mixed up or something stupid like that. The new radiator has both ports on the bottom but I posted about it previously and am fairly confident I now have them correct http://www.vwdiesel.net/forum/index.php?topic=34048.0. Or maybe I need to re-torque the head studs

Any help appreciated.

[theman53]

Unless you lose coolant I would not touch the studs. The studs and metal gasket will probably never blow out. 200 isn't bad.

[homerj1]

Is the gauge accurate?

[Gizmoman]

Unless you lose coolant I would not touch the studs. The studs and metal gasket will probably never blow out. 200 isn't bad.

Thanks for the response - especially on Christmas day!
IMHO 200 is more than it should be unless I were really pushing it hard - I'm not - just cruising. The system should keep it at least below 190. When it hits 200, I'm confident it would just keep going if I didn't back off. Somehow I must still have air in it. I just checked it with a heat gun after doing a hard run around the block. The pressure tank is at 180 but the radiator near the fan switch is only 117. I jumped the fan and it runs fine. Obviously something is wrong with the cooling system (most likely air). I checked the v-belt tension in case the pump wasn't turning as it should, but it feels tight.

[Gizmoman]

Is the gauge accurate?

I believe the digital gauge is very accurate. It reads from a probe and was quite expensive (if that means anything). The stock gauge on the dash has no numbers but typically never went far past the red warning light in the center. Now it's getting to the 3/4 mark which is much higher than it ever used to get. I know it would keep going if I didn't back off a bit.

[bbob203]

PER CRSMP5 advice I run the coldest thermostat 80c I believe. I can hammer it good for awhile before the temps starting rising.

[Gizmoman]

PER CRSMP5 advice I run the coldest thermostat 80c I believe. I can hammer it good for awhile before the temps starting rising.

That makes sense. I don't recall what temp unit I put in but I believe it may have been the hotter one which would explain a lot.

Dang, have to bleed the cooling system again!

[745 turbogreasel]

I don't think I've had any automotive component bad out of the box more than thermostats.

My first attack would be with an IR Pyrometer to confirm the temp gauges reading, and follow coolant flow as indicated by steadily decreasing temps as you go down the line, looking for an appropriate  drop  across each component. I have  a fancy one, but the $35 harbor freight one is probably just as good if you don't need to measure over 500*F

Your symptoms sound to me like a stat that doesnt open, or not fully, and is fine so long as you stay under about 30% throttle?
Another possibility is as the stat builds up to temp, it spikes and gulps cold from the rad  till the system  equalizes, and you just didn't drive  far enough for that to happen?
many cars have  a temp compensating  board in the gauge to hide this effect, and all my large coolant  capacity rigs do it to some extent.

[Gizmoman]

I have shot an infrared probe at it in several locations after a run and found the pressure tank at 180, the head at 212 and the rad bottom around 130 with the top at 175.

Just went for another jaunt this evening and am beginning to narrow it down to a possible issue. . . It seems my IC isn't cooling (again) and this time it's not the hose size. There's water in it but the air sensor is giving me high readings again. I'll have to check the pump. It's one of those Bosch jobs and cannot pull any water at all - needs to be flooded suction. One air bubble and it stops moving water. I believe the way the pump is tuned, an IC is required and this one is not cutting it.

I did back off the fuel screw 1/8 turn, but promptly turned it back to it's "Giles location" - it really took out the bottom end.
I was hoping to drive it to work tomorrow but not till it's right and I'm not sure what that will require. Right now I'm leaning towards a new frozen boost IC and a new intake manifold.
I did find the top half of the one I butchered in my aluminum scrap, maybe I can just tig the two back together

[wolf_walker]

What brand is the t-stat and where are you picking temp from?

[8v-of-fury!]

I have my entire front of the rad blocked, like even beside the radiator on both sides overlapping the headlights.

When I got on it on the highway, I saw temps leaving the head of 225F, I wasn't too alarmed. I run a 160F thermostat too. Flip the rad fan on for 30 seconds, right back down to 190. It was cruising the highway at 205-210, and lemme tell you the HEAT coming from the dash was GLORIOUS!

[745 turbogreasel]

Don't worry about the brand of the thermostat, just chuck it in a tub of boiling water and watch it not open.
I was pretty pissed when my $45 Wahler didn't open.  Drove around 3 days under 1/3 throttle hoping to clear a nonexistent air bubble.

As an IC test, blow some water/meth preturbo... If it doesn't  help, more IC work probably won't fix it.
It does sound like your IC pump should be located in a bottom hose area though.  I happen to know a sump pump on a Home depot 800W inverter  moves a pretty good volume from a bucket(test reservoir).

[bbob203]

YEA GIZ maybe a water meth system would be nice for you to have?

[Gizmoman]

What brand is the t-stat and where are you picking temp from?

Don't know what brand it was. I am getting the temp from the hose coming from the head (see probe in photo below), so I would expect it to be high. The stock Vanagon gauge is reading 1/4 over what it used to though (3/4's of the gauge)

Don't worry about the brand of the thermostat, just chuck it in a tub of boiling water and watch it not open.
I was pretty pissed when my $45 Wahler didn't open.  Drove around 3 days under 1/3 throttle hoping to clear a nonexistent air bubble.

As an IC test, blow some water/meth preturbo... If it doesn't  help, more IC work probably won't fix it.
It does sound like your IC pump should be located in a bottom hose area though.  I happen to know a sump pump on a Home depot 800W inverter  moves a pretty good volume from a bucket(test reservoir).

I just verified that the IC pump is running and moving water so I'm back to guessing. I suppose I will have to dump the coolant and check the thermostat.  I seriously doubt it's the issue but don't know what else to do at this point. It runs great until I start pushing it - even a small amount. What's odd is that after the larger IC hose upgrade, it was fine - then it wasn't. It runs like it did before the hose change and IC temps are back where they were as well. It really seems like if I could cool off the IA, it would keep the temps down (like it did for a day).

The only odd duck here is the IC I built. It's butt engineering at it's finest with no flow testing. Just rude and crude - hmmm, that should work A Frozen boost IC would at least rule it out but I have no Idea where I would locate the thing near the engine and keep the air flow simple. The nice thing about what I made is the turbo plugs directly into it.

YEA GIZ maybe a water meth system would be nice for you to have?

I designed a nice system for water/meth and have a 200 psi pump, adjustable pressure switch, nozzles, etc, etc. The problem arises when you consider travelling accross country and going from Home Depot to Home Depot mixing the crap up with distilled water. Not to mention another tank, wiring, hoses, blah blah bla.  There's something wrong and like I said the IC is the oddball. The thermostat is fairly easy to check so I'll start there.

[wolf_walker]

For as much money as I see in that one photo, I'd be PO'd too.
Very nice work.

Test any t-stat before install, and don't use parts store stuff.  Behr or Wahler.
And not all waterpumps are created equal either.