'89 4.3L Alpha 1 cooling problem at idle

[Al Mottola]

Just received back from the shop my '89 4.3L which had a Spring service done which included this year a new water pump (every 2nd yr.) Now when it idles for ~1/2 hour the temperature rises to 180 deg, but if you goose the the rpms, it drops down to 140 deg. 140 deg is the normal temperature when crusing. I have seen posts for over heating at high speeds, but not at idle. Any ideas?

 

[tommays]

Re: '89 4.3L Alpha 1 cooling problem at idle

if they just serviced it and it did not do it before this what does the shop say ?<br /><br />whats the lowest RPM it will remaine cool at ?<br /><br />usally not enough water is comeing from the pump ,cloged line ,bad water hose ,old inpeller <br /><br />tommays