Need some input. I have a 2001 C5 LS1. All stock, all original. 34K original miles. When I`m cruising through town at low rpm or slow speed, the engine temp has gone as high as 225 degrees. The outside temp is approx. 75 degrees. I`m not using the a/c. On the highway the temp stays just under 200. Do I have a problem or is this normal? Thanks for your input.

 

Are both fans running?

 

Yes.

 

That seems a bit high for 75 degree weather, Mine runs about 180-200 max in 75 degree weather.
225 isn't over heating, Just on the high side.

 

Might just need a 'good cleaning' of the radiator area. These things are like vacuums, and sweep up leaves, cig butts, weeds, etc. There are some good threads, detailing how to blow air through, and clean that area.

 

I can't get mine much above ~200 even on 90 degree days. How are you all having these higher running temps?

 

the car is designed to run between 190 and 225 F. Even at 250 the car is not over heating. Many members see 250F in a road course.. its nothing to worry about, normal operating temps are in the 190 to 225 range. you don't want to run much below 200 F. the clearances and the viscosity is compromised with too cold of coolant temps the sweet spot by design is 200F to 220 F.
The C5 is a bottom feeder and without a clean ac condenser and radiator , the car struggles to maintain the sweet spot. With the two components being dirty its going to push the upper end of the normal temp range. Designed into the algorithms is a 226 setting for high speed fan operation. 226F is a normal and expected coolant range. Cold temps are much more of a threat to you LSX engine than hot temps. Running consistently below 190F will severely compromise your engine's top end over time.. these motors can see 300 to 400K, and are bench marked at 200K. Run them cold and chances are very good you wont see 200K.
Bill aka ET

 

I'd say mine runs 194-198 95% of the time. Maybe gets into 203-207 when I put my foot into it. Never runs too cold though. I'm just surprised I don't run hotter temps and my radiator and AC condenser don't get filthy since I DD mine.

 

Thanks ET, my mind thinks old school (colder is better) so I worry a lot when my '03z reaches 200+ however your posts on this subject are easing my concerns.

 

Ive posted this many times.. actually too many times over the last 12 years... Tuners who are very professional like a colder motor because they can give you what you pay them for,, that is more horse power. Unfortunately they wont tell you that with the motor, ant a cold motor will take its toll on the engine. you see their job is to make that motor run under extreme conditions of a track environment, for a few hours on the week end. but unfortunately if you are a weekend worrier and you drive your 160 stat LSX car in freezing weather, your coolant will see 160 temps. The stat is designed to control how cold the coolant will get, not how hot it will get. driving at 60 MPH on a 30 degree day will insure your collant will stay at the stats design temp. At 160 F for extended period of time , I can tell you it wont be pretty. WE tested these LSX engine mules in the test chamber under all types of condition. in fact it was how we developed the cold start algorithms for the oil life monitor. Cold engine are bad news for someone wanting to keep their C5 running for a long time.
One of the big problems I've seen here with the general mentality of the average C5 member is their thinking is from the 60's as mentioned above.. this type of thinking is not in your best interest. Its not your grandfather's 1955 Buick Roadmaster. I've done my best to try to educate members into modern new millennium automotive technology.
I butt heads with lots of people, people without any real credentials. Most are shade tree mechanics at best. And most of these guy had a grandfather with a 1955 Buick Roadmaster, who was their hero and taught them everything.
Believe me, GM put most of the money into the body design and the drive train.. Its better than most manufacturers could ever produce. WE had a limited budget to meet a certain demographic and we made and delivered this car on time and within budget.

 

Bill.........Thanks for the excellent info. I`m now feeling better about my car. I`m learning more about these cars everyday.

 

I remember long ago when I was a GM dealer technician that we were told 230..ish was COMPLETELY NORMAL and nothing to worry about. The good thing about your concerns is it motivates you to investigate and maybe see a potential problem and you clean your radiator and condenser....all good!

You just got a explanation from the one guy who knows more about the C5 than any of us here.....ET aka Bill.....take it to the bank!

 

This is one of the first things I learned here. My car runs at 192 on the highway and up to 218 in traffic. As long as it continues to do so I know the cooling system is working exactly as it should be.

 

 

good information

 

Bill (ET) is right on. First fan comes on at 226 and goes off at 217. You can test this easily by just letting the car sit at idle until the first fan comes on, and if the temp goes back down in a minute or so and the fan shuts off, you have a properly functioning system. You can monitor the coolant temp on the DIC while doing this as well.

There was a thread not too long ago about modifying a long-reach air blow gun to make it easy to blow out the radiator/condenser safely. Can purchase it a Harbor Freight and do the simple mods and use it carefully. Blew out a bunch of crap on mine with this tool.

 

ET what is the oil temp. suppose to be at, I have heard 200 degrees is where you should be ?
Steve

 

keep it clean

 

Here's the procedure for everyone's reference:

http://www.toquez06.com/radiator.html

 

Something I learned about this system. The second fan comes on only when the a/c is activated.