Heater

1994 CHEVROLET 1500
15 MILES • 7.5L • V8 • 4WD • AUTOMATIC
Avatar
PODLE88
  • MEMBER
  • 1 POST
i replace the thermostat, and ran coolant through it. temperature gauge will go up to 200 and then back down to 150, while your driving. turn the heat on low, it works, turn it on high or med, it blows kind of hot then go cold. need help.
Dec 27, 2017 at 1:31 PM
Advertisement
Avatar
STEVE W.
  • ✓Experienced Mechanic
  • 15,381 POSTS
What was the temperature rating of the thermostat you installed? Was it doing this before the new thermostat?
First thing would be to verify the coolant level. Low coolant can cause the low heat. Next would be to test the new thermostat to verify it is actually operating at the correct temperature. I have seen thermostats rated to open at 195 that actually opened at 160.
Dec 29, 2017 at 12:32 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle