Two different radiators and a new clutch fan and I'm still having issue with it running hot. I've been through everything -- t-stat, water pump, heater core, you name it. When the outside temp gets above ~70 the truck runs hot, and when I tow, it's blowing coolant out of the overflow.

The *only* thing I can think of is a blocked water passage due to an incorrect head gasket; however, I'm damned certain I double checked to ensure that wouldn't happen.

 

VW - i suspect you've already done this back some time ago, but have you ever drained/flushed your block (drain plugs behind motor mounts) to make sure there's no deposits built up in there ?

 

Is there a thread already on this? I dont want to get off topic from the OP's problem...

 

Oh I think there are several threads on VW's overheating issues.

Your thermostat regulates Minimum engine temp not max temp.
You might get a very slight power increase from a 180 stat but most likely at a cost to economy. It doesn't make your engine run better...
Very over rated in my opinion, but hey give it a shot.

 

not that it's over rated... it is a cheep mod. the more mods you have the better it show's itself. I took my modded 5.9 and swapped in the 195 and did not like it 1 bit. took it back out after about 2 weeks. did not see any noticeable change in mileage but the performance was affected.

 

I just replaced the stat in my 97 ram 5.2. The stat I pulled out of the truck was a 195 degree and I replaced it with a 180. I have ok heat when I'm on the gas but when the truck is at idle the heat sucks also to my temp guage sits at 180 my question is why won't the temp get up to 200 any why won't my top radiator hose get hard and hot but it's hot just not hard and I can take the radiator cap off after I just got done driving for 30 min with no color spraying out and the coolant is not hot on the left if the radiator.

 

A warmer engine DOES run more efficient (Within limits, I'm not talking about overheating of course). Why would car manufacturers run pressurized cooling systems if they wanted their engines to run well below the boiling point of the coolant? You'll notice that all manufacturers aim for that sweet spot just above the boiling point of water. This isn't coincidence. Keyword here: Efficiency (which also implies long service life).


Why's the 180 stat better you ask?

Now, if you're after performance, assuming you've got the correct modifications, a 180 stat could be exactly what you need. Cooler air is dense, and you want to warm it as little as possible when it's scrambling for the next available cylinder. A cooler running engine is also less prone to detonation, which can be tough to troubleshoot, so most people swap to a lower temperature stat with positive results.

rabbler is correct, your t-stat controls your *minimum* operating temperature. Most of the time, this also co-relates to your engine's final operating temperature, given a properly functioning cooling system (and no 'under the hood gremlins' like VW has ).

-JT

 

VW- have you ever looked at your torque converter as a possible issue with your overheating issue?

I just read an article on proper TC stall selection, and the guy makes a great case for overheating because the wrong TC was chosen, or the TC is malfunctioning.. If you are interested in pursuing this, I can get you a link.. Or, you can just google "Stall Speed" and likely read the same thing I did.

 

The hotter the engine runs the better the burn. Till heads warp. Check ac condenser and radiator cooling fins The radiator on both of my truck were plugged. Back washed fin and watch the dirt and those tiny little rocks come out. Worked great on one truck and was the cause of cracked heads on the other witch is under construction. Both will yield 195 stats.the 2wd will get the electric fan kit.

 

I thought I remember reading long ago that certain cylinders run hotter than others. This lead to pinging in those particular cylinders. One fix was to simply put a lower temp t-stat in.

I do know that my 5.2l seems happier when towing w/ the 180 in vs the 195; I do have to swap it out in the winter if I want decent heat in the cabin (but I think the shop that did the heater/evaporator core messed up the blend door or something...but that is another issue).