: 1997 4.6 eldorado up hill over heats



willys1
07-15-09, 01:01 PM
Hello I have replaced and tested just about everything I was guided toward to find this probem of overheating under load. I would like to start by saying thank you all for inviting me to this site. I love my caddy It has 146000 miles and it rides and runs like a dream. I was hoping someone has exsperiened this issue. It seems to be picking up air in the system and causing my gauge to act irratic I do know how to purge the system for air and I am confident of this. Car has had replaced New
water pump,crossover gaskets, new radiator new 16lb cap,new STANT thermostat, I drilled small holes in thermostat to help with trapped air after I tried it new with no holes there was no difference
Tested abd checked
Block tested twice
Checked catyltic converter 400degrees in the front and 500degrees inback when hottest
fans have 2 stages that I noticed.
Any thoughts ?
Thanks Willys

willys1
07-15-09, 01:04 PM
sorry for got to add bypass tube is not clogged I checked
Thanks

zonie77
07-15-09, 01:23 PM
How did you test the block?

Did you check the purge line? Flush the radiator?

willys1
07-15-09, 01:35 PM
Purge line that runs across the top of the motor to the surge tank is clear. Block tested for hydrocarbons in the coolant.
The radiator is brand spankin New.Coolant system appears very clean

Thanks very much Willys

Ranger
07-15-09, 01:51 PM
Belt tensioner tight?

zonie77
07-15-09, 02:09 PM
It sounds like early stage of HG failure, when there is still some clamping pressure but not enough under load.

The HC test would show negative at idle, it would only show positive after a heavy enough load placed on the engine.

willys1
07-15-09, 02:54 PM
Ok I will buy that I still thought there would be hydrocarmons in the system to pick up on.
Thanks

tateos
07-15-09, 09:15 PM
Head gasket.

zonie77
07-16-09, 04:02 PM
Ok I will buy that I still thought there would be hydrocarmons in the system to pick up on.
Thanks


I don't think there would be enough to change the color. I don't believe it is that sensitive.

dimone
07-16-09, 11:02 PM
My block test was gorgeous blue, even after plenty of driving. Then I forced an "episode" with some hill driving near home. Back in driveway, yup, plenty yellow after that. I didn't even have to use the pump because the vapors were still venting. This HG issue can be a really confounding and irritating issue!

zonie77
07-16-09, 11:52 PM
This HG issue can be a really confounding and irritating issue!

AMEN to that!