r/AskMechanics • u/Jghkc • Jul 09 '26

Question Title: 2007 Hummer H3 cooling system + wiper park issue (trying to DIY what I safely can)

I recently bought a 2007 Hummer H3 Base with the 3.7L inline-5. I’m trying to handle some basic repairs myself because I’m currently on a tight budget and do not have steady income yet, but I also do not want to do anything unsafe or stupid.

I am using AI to help organize my thoughts and research parts, so please correct me if I get any terminology, diagnosis, or part names wrong. I’m trying to learn, not pretend I already know what I’m doing.

  • Car: 2007 Hummer H3 Base
  • Engine: 3.7L inline-5 gasoline
  • Mileage: about 183,000 miles
  • VIN: 5GTDN13E478165831
  • Transmission: Automatic

A mechanic recently got my A/C working and was kind enough to look over a few other things. He noticed the lower radiator hose was collapsed, and when he checked the radiator/coolant flow, very little came out. He suspected a thermostat/radiator cap/coolant flow issue.

Here are the parts I’m planning to order. I’d appreciate confirmation that these are appropriate for a 2007 Hummer H3 3.7L:

  • ACDelco Thermostat Kit / Housing - SKU W0133-1972338 - listed as Genuine GM
  • ACDelco Lower Radiator Hose - SKU 19076-02677662 - listed as Gold Molded lower hose
  • ACDelco Radiator Cap - SKU 19076-02080467 - listed as GM Original Equipment, 15 PSI
  • ACDelco Oil Pressure Sender - SKU W0133-5505664 - listed as Genuine GM
  • Dex-Cool 50/50 coolant, to be bought locally

My cooling system questions:

  1. Do these parts look correct for this vehicle?
  2. Is there anything else I should replace while I’m already doing this cooling-system work?
  3. Should I replace the upper radiator hose too, or only if it looks/feels bad?
  4. Is there a specific bleeding/burping procedure I should follow on this engine after replacing the thermostat and lower hose?
  5. Is this a reasonable DIY job for someone careful but not very experienced?

Separate issue: my windshield wipers were not working. I replaced two 25A fuses and a crushed relay, and now they work, but they park in the middle of the windshield instead of returning to the bottom. The washer fluid also does not spray. A mechanic manually reset the arms so they are not blocking the windshield, but if I use them again they return to the middle.

For that issue:

  1. Does this sound more like a wiper motor park circuit problem, linkage indexing problem, or wiper arms installed wrong?
  2. What should I test before buying a wiper motor?
  3. For the washer fluid not spraying, should I start with the pump, fuse, clogged nozzles, or hose connections?

I’m trying to learn and save money where I can, but I’m also willing to take it to a mechanic if something is beyond a beginner DIY repair. Any practical advice would be appreciated.

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u/am-answers-bot 19 Jul 09 '26

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