JayTheCPA
Well-Known Member
The Burb’s heating system recently downgraded from a heater to a warmer and am looking for a good set of schematics to figure out where potential choke points may lie; I tried to fish-around on GMPartsGiant, but not really getting a good lay-out of the heating system. Had the mechanic work on the lack of heating, but still far from right; recent repairs:
> replaced thermostats (dual system, and likely with 180*'s as the OBDII gauge shows 183 fairly consistently and the dash tends to hover just over 180).
> replaced the dash heat exchanger (asked to replace the distribution box as well as it is getting wonky (still routes the air properly, but it needs the fan to help the flappers switch positions); however this did not happen).
> recently (about 700 miles ago) had one of the plastic ‘T’ connectors replaced, but the heat seemed to work normally immediately after that repair. Not sure this is a factor, but will toss it out: I had to add 1 gallon of Peak generic coolant (50/50 mix) just prior to the ‘T’ connector repair to get me to my destination and have not purged the system.
Reasons I am thinking there is a choke point somewhere other than the dash exchanger are:
> both the front and rear systems only get to the same mildly warm-air level at the vents.
> (As noted above) The engine coolant is running 180 – 185, but am getting only a fraction of that in the cab (am guessing in the mid 80’s) which after 30 minutes the cab is still very cool.
> air temperature at the vents does not get even slightly warm until *long* after the engine comes up to temp.
One interesting observation is that since replacement of the thermostats, the dash temperature gauge rises faster than the OBDII during warm-up, but both track together when the engine reaches operating temp (Example: this morning outside was ~30F, when the dash gauge started to come off of 160, the OBDII indicated 104F); prior to the replacement, both gauges were in synch all the time.
Just for grins, I topped-up (not off) the coolant reservoir last night, but no change in results this morning.
Will appreciate any troubleshooting tips, links, pics, and / or diagrams to help keep down the costs of chasing this ghost.
> replaced thermostats (dual system, and likely with 180*'s as the OBDII gauge shows 183 fairly consistently and the dash tends to hover just over 180).
> replaced the dash heat exchanger (asked to replace the distribution box as well as it is getting wonky (still routes the air properly, but it needs the fan to help the flappers switch positions); however this did not happen).
> recently (about 700 miles ago) had one of the plastic ‘T’ connectors replaced, but the heat seemed to work normally immediately after that repair. Not sure this is a factor, but will toss it out: I had to add 1 gallon of Peak generic coolant (50/50 mix) just prior to the ‘T’ connector repair to get me to my destination and have not purged the system.
Reasons I am thinking there is a choke point somewhere other than the dash exchanger are:
> both the front and rear systems only get to the same mildly warm-air level at the vents.
> (As noted above) The engine coolant is running 180 – 185, but am getting only a fraction of that in the cab (am guessing in the mid 80’s) which after 30 minutes the cab is still very cool.
> air temperature at the vents does not get even slightly warm until *long* after the engine comes up to temp.
One interesting observation is that since replacement of the thermostats, the dash temperature gauge rises faster than the OBDII during warm-up, but both track together when the engine reaches operating temp (Example: this morning outside was ~30F, when the dash gauge started to come off of 160, the OBDII indicated 104F); prior to the replacement, both gauges were in synch all the time.
Just for grins, I topped-up (not off) the coolant reservoir last night, but no change in results this morning.
Will appreciate any troubleshooting tips, links, pics, and / or diagrams to help keep down the costs of chasing this ghost.
