dampermanatee

Hi, i have read a lot about bad relay and obstructed radiator but it is not my case. i think the problem is the water pump imperler bu before changing the water pump i would to get some advise if i didn't miss something. The temp goes up like crazy when the engine idle even if i'm on the highway at 100kmh (60mph) obviouly i'm on neutral. still on neutral if i rev up the engine at 3000-3500rpm i can see the temperature droping realy fast wich lead me to a flow problem when the water pump turn slowly. It's a 99 coupe ls1 manual transmission 125 000km with only an intake and an axle back.

Thanks

Rob 02

The thermostat may be failing.
There could be air in the system.
You could have a sending unit malfunction.
The water pump impeller may be clogged or corrected (less likely).
Are you sure both fans are working properly?

dampermanatee

The hose are totaly normal when cold and hot too. I forgot to mention i'm located in quebec so it was 15c yesterday. For the fan not sure both are working but in town i hear it realy loud and at 60mph it shouldn't needed. before i was runing at 220 on the highway and now i'm runing 240 it i put it on neutral it reach 255 witting 5second and it i rev it up it drop to 220 whitin 5 second too. for the bad sending unit i will check it with my scanner tonigth at cold if it read the same as the outside temerature.

Thanks

dampermanatee

Thanks for that post i tried this but it doesn't resolve my problem i will try a new t-stat anyway i was planing changing it for a 160* so it's not lost. Tonigth it was ideling at 240 with both fan turned on and it's 12c outside so there is no reason for the car to idle this much high and on the highway i got 240 to 265 wich i to high too.
I forgot to check the reading of the temperature sensor at cold i'll try to remember that tomorow.

Paul 75 L82

That is too hot for the conditions, I would start with a new radiator, they are cheap. If it was my motor I would also buy a new pump and stat. You can buy all for $500 to $600.

foggy

Also get under the front nose and check for debris - like a plastic bag - stuck
up in the radiator/condensor. these are bottom feeders!!!
Also, I would not put in a 160* Tstat in your area.. LS1's like to run warm.
A 180* would suffice... You can do your own research on LS piston to wall clearances,
alum blocks, ideal coolant temps.. Just trying to help

dampermanatee

I looked at the radiator at first hooping it was that but it's clean.

For the 160 t-stat it ordered so it's to late i do not usualy drive the car when it's cold i'm about to store it for the winter i tougth it was a good idea for track day in summer it's more around 25-35C. But thanks for the input I will check the temp and if needed i'll put a 187*.

Annother thing to mention my overheating problem started after my first (and only for this summer) track day and the last owner never been to the track with this car.

dampermanatee

I changed the t-stat and it's cool now. I tried to check for temp and didn't found anything on none recomended 160* t-stat so if you have any information about this on hand it would apréciated. btw i don't drive the car in winter i will get it stored by the end of the month.

thanks 8vette7 for the bleeding procedure i got iall the air out the first time.

sirdano

Are you missing any of the front air dams?
That would be theses parts

https://www.ebay.com/itm/FRONT-SPOIL...ZYkZKA&vxp=mtr