Modified Thermostat for higher MPG's...

Or just use that chip to send the signal to the existing fan controller. Greatly simplifies the install if all you are faking is the temperature from the radiator fan thermo switch.

Jason

PWM fan control

This is the fan speed control that i am using on a car that I built, it works just as advertised. No problem so far. Very nice because it senses the temperature of the water LEAVING the radiator and controls the fan with a PWM output. You can actually watch the fan slowly spin as it starts. It also uses a "soft start" ramp during turn on so that there is no huge current draw. The water temp. is adjusted with a ten turn pot.

Here is the link:

http://dccontrol.com/constant_temperature_controllers.htm

87homebuilttdi said:

This is the fan speed control that i am using on a car that I built, it works just as advertised. No problem so far. Very nice because it senses the temperature of the water LEAVING the radiator and controls the fan with a PWM output. You can actually watch the fan slowly spin as it starts. It also uses a "soft start" ramp during turn on so that there is no huge current draw. The water temp. is adjusted with a ten turn pot.

Here is the link:

http://dccontrol.com/constant_temperature_controllers.htm

Click to expand...

That is extremely nice A bit too rich for my blood. It does offer some nice features like the soft start for instance. I'm expecting the answer to be no, but I 'll ask anyhow....Have you noticed and fuel economy gains from the reduced electrical loading on the charging system?

FWIW the Click PLC setup would be around the same price but offer reconfigurability via the use of ladder logic. It can also be used to control other independent engine systems and components.

how warm are you guys running you car at cruise down the highway?

My current Hybrid thermostat isn't keeping it's designed temperature due to it's age. I need to remake a new one. When is was performing optimally it was running around 209 Deg F on the highway on flat highway stretches. Now it runs at 202

and how do temps look if you get caught in city traffic in the summer months? FL should be lots of 95*F+ days?

mac11 said:

and how do temps look if you get caught in city traffic in the summer months? FL should be lots of 95*F+ days?

Click to expand...

I have my stage I fans disabled on my car so my situation is a bit different. 95% of the time my car does just fine in the hottest months even when in traffic. Only twice have I had to take action to reduce temps(turn AC on to force the stage II fans to come on high. If my fans were fully functional and had a switch that turned them on at 210 F it would be perfect. Go back to about the middle of this thread and read some of that. it may answer some questions for you.

I wanted to update this a bit here. The other day I installed a coolant system pressure gauge to monitor coolant system pressures to make sure I have enough after boil protection. Remember I'm still running standard coolant right now so that is something for me to factor in. Some of you with the Evans coolant don't have to worry so much about it. It runs between 6-9.5 psi over all temperature ranges I have experienced. Even with warmer coolant temps It won't get close to the 15psi pop off pressure of the rad cap. FYI

josh8loop said:

I wanted to update this a bit here. The other day I installed a coolant system pressure gauge to monitor coolant system pressures to make sure I have enough after boil protection. Remember I'm still running standard coolant right now so that is something for me to factor in. Some of you with the Evans coolant don't have to worry so much about it. It runs between 6-9.5 psi over all temperature ranges I have experienced. Even with warmer coolant temps It won't get close to the 15psi pop off pressure of the rad cap. FYI

Click to expand...

After you reach operating temperature rev. you engine to 3000 rpm and see if the pressure increases. I have heard the water pump can add to this figure substantially.

Well I am getting 180 degrees out if the main vents on blower setting 2 at 35 outside temp with my setup. So, what are you all measuring with your setups?

I know this may be a little late in the discussion but I just wanted to let people know, for those who are interested, that Napa sells a 205 degree thermostat that works just fine. It is what they came up with when I asked for a Stant 13352. I already had a 195 from Napa that I was going to put in, so it only cost me about $9 more to do the upgrade. I didn't use any special tools or techniques to do the swap, just grab a hold of it and pull it apart, then push it back on the new thermostat. Simple, and you can't damage anything with your bear hands. Then I gave the other half of the stock 195 degree to my brother to put in his Cummins because 180 degree was the hottest the parts stores had for his engine.

I don't know if people know how interchangeable thermostats really are. The 13352 Stant fits just about any American made motor back to the 1950's. (You can buy one from Summit racing for about $4.95, but by the time you add shipping it works out cheaper just to go to the local auto parts store.) One other thermostat that might work, although I have not checked it out is a 205 degree for a Powerstroke diesel. I didn't look into it because it was more money, but if you otherwise would have to buy two thermostats it might be worth having the parts guy bring up to the counter to have a look at.

Thanks to Josh and everyone for the great thread!

Went t check the factory stat at the dealer. The springs on there are so strong I could barely push the bypass spring with my thumbs. also it is completely sealed as I could not suck or blow any air past the valve. I have tried all these tests with aftermarket brands and they all bypass some air and they all had extremely soft bypass springs. Last time I did this with my factory stat it appeared to have the same results but I couldn't push the main spring so I suspected it was weak or the wax was opening at a lower temp. Trust me even when I was pushing the car hard up a grade loaded it would barely hit 180 and then cruising at 65 I was down to around 160. Today is a great example, the car warmed up to about 140 and after 1/2 hours it cooled off to about 74. If the factory stat was fully closed and peefectly sealed I do not believe it could or would have cooled off so fast. Ambient temp is 46. I think there is a thermo siphon effect happening. They seal so well how do you bleed a new stat in the system lol there is no air bleedand on one side the coolant just acts as a heat sink. Eventually it will open but it takes a good long while of running really hot for it to open. Thats been my experience. I really like the factory stat I may just replace that just tocsee the effect and leaving my stat in the upper hose I can raise temps that way which is real easy and convenient. Maybe 205 is too hot but I can always go down.

The reason aftermarket and most car thermostats have weak springs is because they are designed to be on the outlet side of the water pump and open against the coolant pressure( the pump flow/pressure is trying to force it closed). The stant is a perfect example of perfected design with minimal materials and still function correctly if located between the outlet side of the pump and the inlet side of the radiator with the wax motor facing into the flow.

Also to warm the wax motor and cylinder head and prevent the pump from captivating or churning, hence the bypass requirement. The wiggle pin or slight leakage is usually to bleed any trapped air.

VW put their thermostat on the intake side of the water pump. They have a perfectly designed system. All high points have hose bleeds and the thermostat has an internal bypass. The bypass fully closes at 213 degrees. How do I know that. Because I read and listen to what others are doing and saying.

Josh said when he had a chance to see the bypass opening and said he estimated it to be .250 in. In another post Josh then did the thermostat measurement video. I noted that it required 1 degrees to move the dial indicator approx. .010 thou. or 25 degrees F. to close the .250 by pass.

Now I want to listen to you but at the same time you have to listen to me. You now think it might be the wax causing the stock spring to operate incorrectly. The wax degrades at a rate of a couple degrees a year.

The thermostat responds very slowly. Again the video back a page on this thread shows this. The test shows that a stant thermostat opens 10 degrees higher than the rated setting but closes exactly at the rated setting.

Try making a 205 as #731 did. After you try that add a 195 degree to your inline. You need to get the inline to open before the 205. See if the results are any better. Insulate the hose the inline thermostat is in to get it to respond faster.

Edit: if after trying this, you have eliminated the temperature spikes with this set up, then it is worth trying your 205 inline again along with the modified 205 in the stock location.

It is a must to have the inline open before the 205 stock location bypass closes(with the 205 in the stock location the by pass closes at 205 + 25 or 230 degrees ).

With your old stock(dead) stat it was closing the bypass(160 plus 25 or 185) and causing cavitation because the 205 inline was not even close to opening( opens at 205 + 10 or 215). What do you think? It would be an interesting test.

dieselfuel said:

Shoebear,

Just cut to the chase and use the Evans HDTC. As a bonus, it will not corrode your cooling system (the heatercore is a real, no pun intended, bear to replace).

Running Evans and very satisfied,

df

Click to expand...

I just ordered my EVANS today for my project (Golf3 AHU) http://forums.tdiclub.com/showthread.php?t=305898

Was wondering what thermostat you were using specifically. Yes trying to get through this thread... one post at a time

josh8loop said:

Just realized something this afternoon. Ever since I did the 5-speed swap, my car hasn't sounded the same. Initially my IQ with the auto was at 5.5, and after the swap it went to .6 After I got that straightened out(set to 3.8), I noticed my car didn't seem to want to start the same as it did before the swap. I kinda wondered if my IQ changed when I set the ECM to manual why couldn't the Adaptation timing also change itself with the remap. Sure enough today I looked and it was at 5.5 degrees advanced, and I know before the swap it was at 3.8 degrees advanced. I'm pretty sure I don't remember changing anything in adaptation with regard to timing-could it have changed when I recoded to the manual?

Click to expand...

I am still working my way through this thread so sorry for this (years') old quote but... you do know that the automatics have smaller injector nozzles than the manuals right? It's a weird combination of larger plunger pump but smaller nozzles on the ATs shouldn't hurt your MPGs but just saying..

As I understand it, the problem of employing the Stant 13352 is that it is fundamentally different in appearance to the original-fit 13379, so the technique of hybridization is to take the innards of the 13352 to the 13379 (sorry that I don’t use the jargon of the thread). So if I may ask the stupid question, josh8loop made reference in his post in early 2011 regarding P/N 14252. Visually, it looks like what the 13379 should be with the lower circular plate and lower spring. Can’t this part be used instead and forget about hybridizing?

Having these custom made shouldn't be any big problem as long as there is "healthy demand"

Long time since I've visited this thread.

I'm using a T-stat that Josh assembled from two different Stant t-stats.

I'm still seeing a max temp of 234F through the VCDS. I installed this t-stat in August of 2011 and haved logged just under 50K miles.

I'm going in for a TB change a week for tomorrow. At that time, I'm having a Franko6 Satge II cam and a set of cam followers installed.

Currently, I have 195k miles on my 2003 Jetta that we purchased new in Sept. of 2003.

I can honestly say, my TDI has never run better than it is running today.

Later in the year, I'm replacing the intercooler with an aftermarket one I bought off e-bay from ILoveTacoTaco. And late summer/early fall, I plan on adding a 17/22 turbo.

df

You guys running hybrid t-stats, what temp are you seeing as reported by VCDS?

Like I've stated here, I see a max of 234F. In the coolant tank, I've measured 212F with the same digital thermometer you see in Josh's videos.

Thanks,

df

Well, two cautions I would throw out there for everyone. If you are doing performance mods like bigger nozzles and turbos I would stay with factory t-stat temperatures. You have a much smaller margin for error if something breaks or tune is not perfect. Also both the factory and aftermarket lower the cooling temperature for power. VW actually builds a couple models with variable t-stat to get the best of both.

Second we see a lot of the other plastic parts in the cooling system break down when the engine gets hot or overheats. At the shop when we see large cooling fan failures, they precipitate t-stat and water pump failures. Also the coolant flange, heater core hose barbs, the cross over pipe on VR6, tees and elbows in the radiator hoses get brittle and break easily.

Maybe a good suggestion for long term durability would limit max temp to 200-205F. That is still a healthy bump from 185F of the stock t-stat. I'm not saying that all the pipes and plastic will just explode, but when you do work on the engine all the plastic parts will snap easily.

Jason

^ Good advice there. But I think most of the people represented in this thread are more in an economy bent than performance...

If it helps anyone, here's a P/N cross-reference matrix for the Stant 13379. There are several Wahler P/Ns for 92C (198F) parts, in addition to several other P/Ns scattered throughout this burgeoning thread. From reading df's report of 234F temps, I'll probably try one of these instead of a 205 as a conversion to Evans coolant, which I consider a requirement with the 205 thermostat for my own engineering sense of safety, is not in the cards in the near future.

TDIMeister said:

As I understand it, the problem of employing the Stant 13352 is that it is fundamentally different in appearance to the original-fit 13379, so the technique of hybridization is to take the innards of the 13352 to the 13379 (sorry that I don’t use the jargon of the thread). So if I may ask the stupid question, josh8loop made reference in his post in early 2011 regarding P/N 14252. Visually, it looks like what the 13379 should be with the lower circular plate and lower spring. Can’t this part be used instead and forget about hybridizing?

Click to expand...

Anyone ever reply to this?

It was replied to and it can be used but it only adds about 7F since it is a 195 tstat, if you want a higher temp you need to go custom.

I will be going to the 195 myself but that is because I'm going to keep my grill blocked as much as I can. As long as i can keep the AC getting fresh cool air.

Phantomofheat said:

It was replied to and it can be used but it only adds about 7F since it is a 195 tstat, if you want a higher temp you need to go custom.

I will be going to the 195 myself but that is because I'm going to keep my grill blocked as much as I can. As long as i can keep the AC getting fresh cool air.

Click to expand...

You're saying this isnt really a 205F thermostat?!

http://www.stant.com/modules/partLocator/view_diagram.cfm?id=14252

Looks like some BMW models use 203F stock

http://www.ecstuning.com/BMW-E34-530i-M60_3.0L/Engine/Cooling/ES24828/

Good for research (dimensions in the back)
http://www.stant.com/repository/files/2012 Stant Pass Car Catalog.pdf

G3TDI said:

You're saying this isnt really a 205F thermostat?!
http://www.stant.com/modules/partLocator/view_diagram.cfm?id=14252

Click to expand...

That is a 205F but the dimensions are totally differant.

The one above is .4" wider, 1" shorter, and .1" narrower on the bypass compared to 13379

Phantomofheat said:

That is a 205F but the dimensions are totally differant.

The one above is .4" wider, 1" shorter, and .1" narrower on the bypass compared to 13379

Click to expand...

Yep figured that out already

Just ordered the Stant ones mentioned earlier in this thread and will build
my own hybrid one tomorrow then pour in the Evans

G3TDI said:

Yep figured that out already

Just ordered the Stant ones mentioned earlier in this thread and will build
my own hybrid one tomorrow then pour in the Evans

Click to expand...

I have had Evans in since last June. All is well. I converted the pressure cap to a zero pressure system at that time. This allows any residual water in the system to slowly escape the system, leaving only Evans behind.