I installed my Hypertech thermostat and now my engine temperature varies from 180-185 approx. (171 per Atap)driving, to 200-205(189 per Atap)at idle. It heats up quickly too which acts like the thermostat has two settings. An idle setting and a driving setting. No matter how long it idles it does not get any warmer than 200-205. This is the same temperature as my stock thermostat at idle or driving. This is in 40 degree temperatures too. If it were doing this in hot summer I would assume the radiator is just not getting enough air flow.

Never had a thermostat operate like this. Normally when you sit and idle the temperature works it way up slowly. With this Hypertech it will heat up by the time the light turns green. It's that quick. Seems like the thermostat closes off at idle until 200+ degrees.

 

Mine does nothing like that. It sounds like you got a bad one. The only time mine even moved once the engine was warmed up was one time when I was backing my travel trailer UP a hill, then it got hot. Other than that, it does what it should do.

 

mine stays at 180 or 185. only time it even gets close to hot is in the hot summers stuck in trafiic.

 

On my 01 L my 160* 'stat keeps the coolant temp at 75-77C or about 169-171*F. This was with 65*F outside temp. and driving 60 mph and idling.

Dan

 

hello it sounds like you should bleed the air out somemore my engine runs 150 deg all the time with 160deg thermostat

 

ASP replaced this Hypertech thermostat with another and problem gone! It stays about the same temperature now. About 180-185 accordiing to my gauge and never gets up to 205 anymore. I can't imagine how the thermostat even managed to do this but in any case it is fixed now.