I posted a while back about a 180 hypertech thermosatat running hotter then I thought it should (190-194 in 40 degree weather on the highway). Also noticed it would get to 210 or so when idling for 10 minutes, bring the RPM up 200 rpm and it would come right down - this in 37 degree weather. When I had the radiator out swapping the cam I flushed it and cleaned about 5lbs of florida sand from the fins - it was loaded. Figured I solved that problem.

Cam and u/d pulley go in last week (only 10% underdrive) and now its hitting 210 after idling for a minute after its warmed up. Had a water pump from an '02 here so I swapped it - same. Took out the 180 thermostart (which is not a shimmed stock unit it is a german made motorad that is marked 180 right on the element) did the boiling water test, opened right at 185 and was fully open by 190. Put it back in. Drove another C5 with an ASP pulley (25% underdrive pulley) and stock thermostat with fan programming yesterday, it never ever went above 196 - even after idling for 20 minutes, I'm like wtf. I also noticed that when mine idled the right fan was drawing cold air and the lower hose was cold with the engine at 210.

Just for the heck of it I put a .080 shim in a new stock thermostat and stuck it in - car never never goes over 192 idling now until the fan shuts off at 190 and its at 187 on the highway in 50 degree weather. So I put the 180 stat back in the pot on the stove - working fine. Put it back in the car, same thing - hot at idle, fine above 1500rpm. I can pretty much say there is something up with this thermostat :)

Only difference I see is on the bypass valve, the motorad has a shaft that moves with the thermostat and may hit the back of the water pump when it opens keeping it from opening fully (I didnt measure and I dont think it will hit) and not letting enough coolent through at idle. I have used these thermostats in dozens of LS1 cars and never had a problem - but all it takes is one, mine of course. With a high mileage car like this I blamed everything else but the thermostat, it was one of the newer things on the car.

Sorry to be so long winded about a 45.00 part, but this has been bothering me since it got cold out. After draining the coolent and filling it five times in the last 3 days I'm glad it got better - maybe it will help someone down the line :cheers:

PS, if anyone wants this 180 stat to try, its yours :)

 

"kp", you're not the only one who had problems with a Hypertech 180 degree t'stat. I had one in my 2001 coupe for about 2 weeks... car ran hotter than with the OE piece.
I put an 0.080" ship behind my stocker, and now the car runs at 182-185 degrees, even in hot weather.
The Hypertech t'stat was a waste of money, IMHO.

 

I have read of problems so I know I'm not the only one. I figured I would give all the details so someone doesnt say its your water pump, radiator, pulley, air in cooling system, etc and not the stat.

I have used the same style motorad stats in three of my other LS1 cars and a lot of customers cars and never had a problem before. I have no idea why this one doesnt work since it sems to work fine on the bench..

 

Can you elaborate on the shim you used and how you placed it into the t-stat? I changed the one on my Coupe to a 160*, and the car ran around 172*......I've been thinking about changing the one on my Z, but think that I'd rather just shim it......just don't know what type of shim you use or where to get it. I checked in the tech section https://www.corvetteforum.com/techti...php?TopicID=1) and there's no topic for it, this would be a good one to add though.

thanks


[Modified by Z06 Quin, 11:02 AM 12/12/2002]

 

http://www.ls1info.com/article.php?sid=180
This is one article, some stats wont take too large of a shim but it works..

 

I bought a Motorad 180 degree thermostat from TPIS used for $20. It opens and closes EXACTLY the same as my stock unit. TPIS said that the stat was operating fine -- that my temp. gauge was off. After calling TPIS several times and mentioning that other forum members had the same problem they said that the gauges in C5s were all off!! I have a Hypertech and have set my fans to come on at 209 degrees. Well now my car NEVER runs over 209 degrees! I would say this proves that my gauge is not off. ( Unless the Hypertech is also off the same amount. ) The guy I talked to at TPIS is over the garage, and I believe his name is Jim. This goes to show how bad the info can be even from a vendor such as TPIS. He did refund my $20 though, but I'm still out $35 for the install ( I have MD and couldn't do it myself ). :mad


[Modified by 1g1yy, 5:32 PM 12/12/2002]

 

Thats OK, my wife has an MD and a PhD and she cant figure out where to put the ww fluid - love her to death though :)

I'm not bashing motorad or hypertech, I have used many with no problem. Problem was when I bought my car the radiator was completely clogged with debris, the dexcool was dexsludge, the idler pulley was almost siezed and the belt was shredded pretty well. I changed everything (including the thermostat) all at once. Plus it was in the middle of a hot summer so I didnt think 210 in traffic with the a/c on was so horrible. When it started dropping into the 30s and the car was still idling at 210 with the fans on high that i started getting concerned. :cheers:

 

I called Hypertech to complain about my t'stat, and the "tech" there said that their t'stat was OK, but I had to reprogram the fan turn on in order to get everything working properly.
When I asked why, because the stock 195 degree t'stat ran cooler that their 180 degree unit, he started mumbling some gibberish. I told him he had no idea what he was talking about and hung up.
At that point, I was looking through the tech articles here on the forum, and found the t'stat mod instructions. In order to make a "shim", I used a 1/4 " stainless steel screw that had a long shank. I cut off the threads, and trued up the end in a lathe.
I then measured the inside diameter of the housing of the t'stat, where the stem of the poppet valve goes in, and turned the screw so that it's OD was about 0.010" SMALLER than the hole in the housing. Then cut off an 0.080" thick slice of the screw, put it in the housing, and reassemble the t'stat, reinstall it in the car, fill with coolant, and HAPPY MOTORING!!

 

I have a Hypertech 160 t-stat with reprogrammed fans and my car runs 176-178(avg) in hot Miami.... :cheers:

 

I had a 160 stat put in two weeks ago. Today in 68 degree weather and some hard driving, my water temp stayed around 172 and my oil temp topped out at 199. Speedworks did program the fans to come on earlier.

Based on the current weather, I think this setup should be perfect for the next Texas summer :cheers: