Questions and Answers

Grand Cherokee Losing Its Cool Q. Dear Vincent, I recently purchased a 1993 Jeep Grand Cherokee from a private owner. The vehicle has 135,000 miles on it and it has a 5.2 V-8 engine. For the first few weeks it ran great but then I had to replace the fuel pump which was not cheap. But the problem that I am writing you about is the air conditioner.

Whenever I run the A/C, after about twenty minutes, the temperature gauge rises near the danger point and the engine begins to shake. When I turn the A/C off the engine and temperature gauge return to normal. What could be causing this?

A. The cooling system is not able to handle the extra heat load of the A/C system. Most likely the water pump fins are worn down and not circulating coolant properly or the radiator is partially clogged.

I would recommend doing a cooling system back flush, new thermostat and fresh anti-freeze and see what that does for you. If it still has a problem then you'll need to go for a water pump or radiator re-core or replacement.