Kenmore Series 90 repeatedly stops heating

Model Number: 110.63912100
Brand: Sears Kenmore
Age: More than 10 years

Model Number: 110.63912100
Brand: Sears Kenmore
Age: More than 10 years

My Kenmore Series 90 (model 110.63912100) dryer keeps tripping the thermal cut-off fuse - I'm at a loss and would appreciate any help or suggestions (certainly up to letting this dryer go). When I replace the cut-off fuse, the dryer will run for a couple to dozen loads and then trip the fuse again. I have replaced the dryer vent hood and dryer vent hose, and made sure there is good airflow from the dryer out. I have replaced the cut-off fuse, high limit thermostat, heating element and cycling thermostat. The thermal fuse shows continuity so I haven't replaced that. I have pulled the blower motor and the vent pipe to the exterior and cleared it of lint with a shop vac and compressed air. I vacuumed the inside of dryer with everything removed. I have not tested the line coming in for 220 because I get heat with a new cut-off fuse but then it trips so I thought maybe it ruled that out? My wife thanks you for the help, she insists she wants a new vehicle before a dryer.

Yes I also doubt that it would be a voltage problem.

Check that the holes at the back of the dryer drum are clean. Sometimes fabric softener residue can build up on them reducing their size and restricting air flow.
Also do this on the lint filter.
Check the drum seals and the seals at the blower.
Also I think there should be a seal at the heater assembly to the back of the drum.
Check that the blower wheel is not stripped. Sometimes they will strip and still turn but slip when under extra load.

I am assuming that you have already cleaned the blower wheel as any dirt on the fins can reduce air flow.

Sorry for the delay in responding but thank you so much for the suggestions. I haven't been able to get to it yet but I had not thought to check the back of the dryer drum, though I did scrub the lint filter clean and vacuumed the grille and surrounding area well. I think if the seals aren't the problem they definitely could use to be replaced as well. How would I go about testing to see if the blower wheel is stripped and slipping under an extra load? I did clean the blower wheel as best I could (toothbrush and vacuum to each fin) but I did not remove it. I'm wondering now if I should have and if I'd be able to tell if it's stripped once I remove it.

Thanks again for the help - it'll be great to have this fixed but it's also cool learning about it.

Do not remove the blower wheel.
Often the wheels seize to the motor shaft and the only way to get them off is to destroy them.

Hold the motor shaft with vice grips or pliers and then try to move the blower wheel.
If it is stripped it will move.

As far as the drum seals.
The problem here is that if they leak excessively then the air flow is not correct in the unit so the thermostat on the blower sees a lower temperature and keeps the heater on for too long.
Same applies with other seals in the unit.

I tore it down again and checked the blower wheel while immobilizing the motor shaft and the wheel did not budge so I'm interpreting we're okay there. I removed the bulkhead and cleaned behind it along with the heat duct I had overlooked before and inspected the seals. I've ordered a blower housing, lint chute and drum felt seal as they all were pretty ragged or non-existent. The rest looked okay as best as I could tell. If it's not these seals it looks like we're moving on from this dryer. Thanks again for the help denman, I greatly appreciate your time!

You are welcome.

Hopefully your new parts will fix the unit.

Sorry for off topic, but is anybody checking new registration on this website ? Got registered 3 days ago, created a new thread, told me that it needs moderator's approval...Still no approval. Created another one - still nothing.

Sent private message to Doc - no answer...Is this the way how things are working here ?

Are you planning to have a Online Digital Signature Certificate. We are authorised providers of Digital Signature Certificates, partnered with some of the prominent and licensed Certifying Authorities in India. It is a Simple and speedy process with Vakilsearch.

I have a Kenmore 80 series and My Kenmore 90 series dryer has blown 3 thermal fuses. Each last maybe 5 minutes. What can be causing this??

A model number would be useful.

Most common cause is a plugged vent.
Also could be a grounded element of plugged/dirty dryer.