Heat suddenly uncontrollable after installing stop leak in A/C system

[motorscuba]

I recently had some front end damage and as part of the repair I had to replace the condenser in a working A/C system. The condenser was used and from a trusted source from a working A/C system also. After replacing it the A/C worked for a couple of days and then stopped getting cold indicating we had a leak somewhere in the system. The mechanic then put some type of stop leak in the system (we didn't install the freon) but immediately after leaving there the heat was uncontrollably as hot as it could be.

It didn't matter where the temperature control was it was maximum heat coming out. I never had any problems with the temperature controls so I'm ruling this out for now.

I did some research in the forum and found that in the event of a vacuum leak or a stuck flapper the system defaults to full heat mode. We were checking some hoses at the top section of the engine while I was there so I guess there's a possibility of a vacuum leak but my question is could the stop leak have caused this heating problem??

Thanks

[Grandad#3]

You might have damaged the Heater Control Valve at the Firewall when messing with the hoses at rear of engine. Heater Full Heat at all times could be the Clips on the Control Rods are broken. See the link below at Heater Malfunctions as it shows the Heater Clips.

944 HVAC Operation and Malfunctions

Cheers,
Larry

[motorscuba]

Thanks Larry...this looks very helpful. I'll let you know how it works out.

[motorscuba]

Looks like the clip for the control rod was broken Larry...we are replacing it. Thanks for that link!!

[motorscuba]

Clip replaced...heat is gone!!!! Thanks again Larry!!