colinamos

Well let me begin by saying that I am mechanically inclined, but in need of a little advice. I have a 98 cavalier I bought for a winter beater. It has overheating issues so i started with the usual suspects and now im running out of ideas. I have replaced the thermostat, removed and had the radiator checked at a shop, checked all the pipes, backflushed the entire system as well as a chemical flush, and replaced the water pump. I understand these cars are prone to issues with head/headgasket but its not showing any of the usual signs(oil in coolant and vice versa, or white smoke) Unless the gasket has cracked between a cylinder and the waterjacket in the head i assume it would show other signs. Im not yet prepared to replace the headgasket only to find out that there was some trick to bleeding the car and that fixes everything. When the car reaches temperature the thermostat does cycle open and the radiator will get hot as well.I know these cars are notoriously bad for getting the air out of the system so im wondering if anyone has some tricks or any other ideas it could be other then the headgasket. I havent tested for the presence of exhaust in the coolant yet, that will be a final test before the head will be removed. Ive browsed the internet for the last 2 days before posting on this forum. So i hope someone here could help me out. Ive tried to bleed it with the bleed screw on the heater core line, that didnt help. Any advice would be greatly appreciated. Thanks, Colin.

colinamos

It has the 2.2l, incase anyone wants to know.

kevinkpk

Lets talk radiator fans, 1 or 2, and pull push. Does this have a/c? Is the fan running. I assume the radiator has one electric fan?

colinamos

Its got ac, and 1 fan. The fan kicks on when its very very hot, or when i turn the AC on

colinamos

its a pull, as well

tech2

1. pressure test the rad cap

2. is the coolant to concentrated...over 70%

3. measure the temp drop across the radiator and heater core; should have at least a 10 degree celcius drop from inlet hose to outlet. an infrared heat gun works best to take the measurements.

I know most of the coolant should bypass the heater coreand theorectically a blocked heater core shouldn't over heat a car but the tech who works beside me has the same car and engine and said his ran hot due a clogged heater core. (was his rad partially clogged too; I don't know). Do you get good heat output from the heater?

When your checking the rad might as well check the heater core.

colinamos

Yes, the heat is always fine. Its a brand new rad cap as well i forgot to mention that. Oem from chevy as well. Ill check the rad today and ill let you know. Since Im changing the coolant so often fixing different things, im running the car on straight water so i can save money and drain it easily in the event i need too.

tech2

once you get it fixed; get coolant back in it. There are no corrosion inhibitors in water!

BW56

This was my journey 1 year ago today. Made it through an Arizona summer with no problems. I found the heater core worked but needed full flow to open the thermostat, which i didn't have. Bypassing it showed where my problem was, AFTER i looked at EVERYTHING ELSE. Bob https://chevroletforum.com/forum/cav...rything-45692/

colinamos

there we go! That's one thing i haven't tried, i always assumed the heater core was okay because i always have working heat. I will bypass it and see how that goes. Thanks alot for your reply, ill repost the results as soon as I can get around to testing that.