Coolant is boiling in the reservoir tank

DJH51190

MEMBER
1997 CHRYSLER LHS
115,000 MILES

I have a '97 Chrysler LHS, that started overheating. I thought the initial problem was the thermostat, because it would not blow heat. I changed the thermostat twice it is now blowing heat, but now I have coolant boiling into the reserve tank. I cant really see the water pump too well to see if it is the problem, but from what I read I dont think that it is. How can I better check to see if it is the water pump? What may be the problem? Also, could someone give me tips on how to fix this or diagnose?

Saturday, September 3rd, 2011 AT 5:38 PM

3 Replies

JDL

MECHANIC
16,098 POSTS

As far as coolant flow, take the thermostat out, hook everything back-up. Can you see the coolant in your radiator and radiator passages? With cross-flow radiator, drain the coolant down till you can see the top couple of passages. With a cold engine and radiator cap off, start the engine, the flow should be instant. If no flow, there is a blockage or water-pump is faulty.

In degrees F, what does the temp gage show with water boiling? Could be other issues, radiator cap--combustion gases getting into the coolant?

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Saturday, September 3rd, 2011 AT 5:47 PM

DJH51190

MEMBER
6 POSTS

What should I do if I cant see down in the radiator? The radiator doesnt have a cap on top like most. To answer about the temp its running it doesnt say the temp but its running to about the second from H line on gauge.

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Saturday, September 3rd, 2011 AT 6:04 PM

JDL

MECHANIC
16,098 POSTS

Take the heater hose return line loose from engine, not heater core. Don't start the the vehicle, disable ignition, Should have flow with just crank. You may have to have heater turned on to allow flow through heater, at the moment, I'm not sure?

I wasn't sure if had a radiator cap?

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Saturday, September 3rd, 2011 AT 6:21 PM