Drove about 50 miles at ambient temps of 90 degrees. All flat terrain. Turnpike driving at 75 mph. Engine temp continued to rise approaching red zone. Slowed down and over time temps stabilized. Still high in my estimation. I only have the temp gauge in the console. The std gauge.

Took a picture of the thermostat cable and flap connection when I got back home. Reviewed it with a cold engine and compared. The flap control isn't moving. Looks like thermostat is not working as all other components work and are not bound up. This is a hard to find part. Any suggestions for where to go and purchase.

Lastly I've not yet got around to assembling the heat control in the car. I don't have the flaps on either side at the bottom of the blower housing. Neither do I have the lower heat shields installed. I do have the cylinder shields installed on the bottom. Do these components effect engine cooling ??

Appreciate any and all help. Want to get this fixed before Octeenerfest.

Thermostat can be tested by removing and heating gently with heat gun.

If you don't get expansion / contraction it is dead as a final verification.

The thermostat is supposed to fail in the max. cooling position so even if it isn't working, that shouldn't be your problem ...

unfasten the wire at the small tab and see if the flaps go to the default position. You should be able to move the vanes back and forth by hand.

Unless the original thermostat has been replaced with one of this which I believe fail in the minimum cooling position.



Awesome Powdercoating is a good place to get OE style thermostats, cables, and parts.

Just check the position of the flaps. As alluded to, twist the crank and see if it snaps back. It would better to clip the cable and have it warm up slower than overheat later. But don't because as Andy said, they fail safe. I don't know the other thing someone mentioned, it's not common in my world

Then there's timing: Too advanced = higher head temps, too retarded = higher oil temps. It needs to be right.

You would be expected to lose some cooling if you have the fan casing vents that drive air to the heater flap valves simply open to the air. The system takes some of the air used for motor cooling and either runs it through the heat exchangers or dumps it to the air past the moving flap. This has some resistance to flow, so if the entire run is disconnected more air will be diverted from engine cooling, out through the fan shroud openings. I doubt this is a large effect, but may make some difference. I find that when you get up to around 75 mph it starts to take a lot of power to move the car through the air. Then you hit a hill and start to worry. Maybe others have had better luck.

The pic I posted is a Mexican built thermostat that is being sold by some vendors as a replacement for the more expensive OE style thermostat. There is more info on them about half way down this page.

I wouldn't buy one but the fact they are out there means we can't assume everybody's thermostats are fail safe anymore.

I’d put the engine tins in place. They all work together as a system. Are the rubber engine tin seals installed correctly? Do you know if the top of the oil cooler is clean? And/or if the cooler itself isn’t gummed up? If your timing is on and everything else check out, it could also be the sender or gauge. Check the engine case with an infrared thermometer when hot to get a sense of the actual temp...

Engine was rebuilt 2 years ago and now have 1500 miles on it. Oil cooler was new. I do have a few oil leaks which will be addressed when I get back from Octeenerfest. The Melling oil pump leaks at the peripehery. Gasket is paper thin. Oil temp sending unit at bottom of the case also leaks, but don't they all. Plan on doing the billet aluminum replacement.

Rubber around tins needs some repositioning. It is intact completely around the engine bay. Timing is at 31 degrees BTDC.

I did check the heads around the exhaust on the forward cylinders. Was surprised to find the temp on the pass side 50 degrees hotter than on the drivers side. Is this normal ??

After thought now, but you don't need any gasket for the oil pump. 518 locktite and you are good to go. I also don't like melling personally. In a beetle its fine, but I would go blue printed stock first, then Schadek, then a good stock one as far as choices.

Timing seems a little high, but not knowing your setup its hard to determine. If it runs and runs well that might not be the issue. Definitely check the function of the T-stat with a heat gun.

My thermostat works partially, but does not open all the way. The engine was getting very warm after an evening drive, so I loosened the screw on the flaps, then they completely popped open. May be what you are seeing here..

I have seen the cooler flap drop link arm turned so it's pushing the wrong way, insure that the flaps are working correctly.

asked about that Brazil thermostat recently ,hinted about failure rate and fishing but AA didn't take the bait as they sell them,others do also,no issues so far on other forums but if you don't have gauges are you safe from overheating ..buggered if I know but hardly a safe option with the function of this part.