2000 Ford Ranger Cooling System Leak

FORD RANGER
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MUSKSNIPE
  • MEMBER
  • 1 POST
2000 Ford Ranger 3.0 engine 85,000 miles
After the engine warms up to normal heat, the temp. drops, cool air blows from the heater, then the temp. spikes hot for a short period (30secs), and then seems to run normal engine temps. Checking under the hood, I find the coolant overflow tank cap blown off.

I believe my cooling system has a small leak allowing air into it. I can find no coolant. How would I find a small leak?

I have replaced the thermostat and bled air out of the system but I continue to get these symptoms.
Feb 8, 2007 at 12:44 AM
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GARFIELD
  • ✓Experienced Mechanic
  • 197 POSTS
Small coolant leaks are hard to find. The quickest and easiest is to use a UV light with dye that was put into coolant and ran for a short time and use the UV light to find out where it is coming out. It will show as a glowing green color where it is leaking. You can get the kit from Napa and most other auto parts stores. Hope this helps.

Gary
Feb 8, 2007 at 12:56 AM

Suggested Repair

Add UV dye to the coolant, run the engine briefly, and inspect with a UV light for a glowing leak. Dye kits are available at auto parts stores.

Conversation Summary

A 2000 Ford Ranger 3.0 with 85,000 miles drops temperature after warmup, blows cool heater air, then briefly spikes hot before returning to normal. The overflow tank cap is blown off, and no coolant is visible. The thermostat was replaced and the system bled, but the symptoms continue. The expert recommends using coolant UV dye and a UV light to locate a small leak.

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