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mosel70 · 06-22-2017, 02:15 AM

Thanks for the ongoing replies. Still no fix. Ugh! (It was 115 degrees out in Vegas today)

- Update: I checked total timing with vacuum line off and plugged from vacuum advance. Initial was 12 degrees (BTDC) and total was 36 degrees BTDC at 3,000 RPM. That sounds about right. I have a bit of a cam but not sure how much.
- All cooling system components are new.
- T stat is 180 degrees.
- Not bubbling over when engine is turned off.
- As I drive it eventually gets deep in the red on the gauge and 230 degrees on the lower rad hose (bottom of rad to pump) using IR gun regardless if open highway driving or in town driving. Top hose is 20 degrees cooler. Sounds backwards, doesn't it. Summit claims it's the right pump.
- It never pings
- Water pump replaced last summer (Summit high volume pump)
- Nothing blocking airflow. Installed Mishimoto's twin electric fans (2600 CFM total) and their 3-core aluminum rad, both designed specifically for 67-72 C10s. I also temp installed a pusher fan on front of A/C rad (1100 CFM), still over heats, but slower and only slightly into red area on gauge.

The only other strange thing is I've started getting what sounds like belt squealing occasionally when engine is cold. It's not a belt. Torque converter maybe?

Next step is to look hard for any vacuum leaks before installing a new water pump. Keep the ideas coming. They are Enormously helpful!

06-22-2017, 02:15 AM	#27
mosel70 Registered User Join Date: Jul 2016 Location: Las Vegas, NV Posts: 116	Re: Mishimoto Electric Fans in Your 67-72 C10? Thanks for the ongoing replies. Still no fix. Ugh! (It was 115 degrees out in Vegas today) - Update: I checked total timing with vacuum line off and plugged from vacuum advance. Initial was 12 degrees (BTDC) and total was 36 degrees BTDC at 3,000 RPM. That sounds about right. I have a bit of a cam but not sure how much. - All cooling system components are new. - T stat is 180 degrees. - Not bubbling over when engine is turned off. - As I drive it eventually gets deep in the red on the gauge and 230 degrees on the lower rad hose (bottom of rad to pump) using IR gun regardless if open highway driving or in town driving. Top hose is 20 degrees cooler. Sounds backwards, doesn't it. Summit claims it's the right pump. - It never pings - Water pump replaced last summer (Summit high volume pump) - Nothing blocking airflow. Installed Mishimoto's twin electric fans (2600 CFM total) and their 3-core aluminum rad, both designed specifically for 67-72 C10s. I also temp installed a pusher fan on front of A/C rad (1100 CFM), still over heats, but slower and only slightly into red area on gauge. The only other strange thing is I've started getting what sounds like belt squealing occasionally when engine is cold. It's not a belt. Torque converter maybe? Next step is to look hard for any vacuum leaks before installing a new water pump. Keep the ideas coming. They are Enormously helpful!