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Coolant system help?

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Old Jan 31, 2011 | 07:49 AM
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Lightbulb Coolant system help?

Neophyte Cherokee owner here, and could use some help.

I have a '97 Cherokee Sport that stopped blowing heat suddenly, followed by spikes in the temperature gauge. The shop says there are leaks in both the radiator and the water pump (diagnosed via a pressure test), and that the thermostat should be replaced as well. Two questions for the group:

1. Does it seem reasonable that the water pump would leak, or is it more likely that it will fail (and not circulate coolant)?
2. Shop tells me that it's "highly recommended" to replace the thermostat at the same time as radiator. Anybody here recommend this?

Thanks!
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Old Jan 31, 2011 | 08:56 AM
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When the rad is out, one could change the water pump, t-stat and its housing, the fan clutch, all while blindfolded, then install the new rad.
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Old Jan 31, 2011 | 09:10 AM
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Originally Posted by newjeepster
Neophyte Cherokee owner here, and could use some help.

I have a '97 Cherokee Sport that stopped blowing heat suddenly, followed by spikes in the temperature gauge. The shop says there are leaks in both the radiator and the water pump (diagnosed via a pressure test), and that the thermostat should be replaced as well. Two questions for the group:

1. Does it seem reasonable that the water pump would leak, or is it more likely that it will fail (and not circulate coolant)?
2. Shop tells me that it's "highly recommended" to replace the thermostat at the same time as radiator. Anybody here recommend this?

Thanks!

Most of the time the water pump will leak before it fails completely, but not all the time. yes when replacing rad an water pump I would replace t-stat as well. I would also back flush the heater core at the same time.
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Old Jan 31, 2011 | 09:10 AM
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If you can do some wrenching on your own, you can go here to see the write-up https://www.cherokeeforum.com/f51/co...upgrade-69207/

Welcome to the site, I'm relatively new here myself, but there is a TON of good info on this site if you search a bit and look around. The Technical/Write-Up section has a lot of good DIY info with pics.

and yes, if you're going to change the radiator out, the water pump and thermostat and housing should be replaced as well. Since they're "relatively" cheap insurance especially if they have not been serviced recently.
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Old Jan 31, 2011 | 09:14 AM
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Originally Posted by thundaluvin

Most of the time the water pump will leak before it fails completely, but not all the time. yes when replacing rad an water pump I would replace t-stat as well. I would also back flush the heater core at the same time.
X2
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Old Jan 31, 2011 | 09:18 AM
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The water pump has a seal on the shaft going to the pully. That seal failing is the most common reason to replace the pump.
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Old Jan 31, 2011 | 09:32 AM
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Thanks for the replies. So, it sounds like replacing all three is not a bad idea if rad is dead.

In further developments, I'm taking 'er to a different shop for a second opinion. When I picked it up from the first place, they said the rad is "bone dry." Luckily I'm not going far. But when I looked, the reservoir was half full. Also, once it reached operating temp it held steady and was blowing plenty of heat (unlike when the problem started and was getting no heat with temp gauge spikes).

It doesn't seem like this is indicative of rad being bone dry, is it? I'm thinking no coolant would result in steady increase in heat way above operating temp, and cold air through the heater (since no hot coolant getting to the heater core). Am I missing something?
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Old Jan 31, 2011 | 09:35 AM
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Originally Posted by djb383
When the rad is out, one could change the water pump, t-stat and its housing, the fan clutch, all while blindfolded, then install the new rad.
I might try it without the blindfold first; I gotta crawl before I walk...
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Old Jan 31, 2011 | 09:35 AM
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Originally Posted by newjeepster
Thanks for the replies. So, it sounds like replacing all three is not a bad idea if rad is dead.

In further developments, I'm taking 'er to a different shop for a second opinion. When I picked it up from the first place, they said the rad is "bone dry." Luckily I'm not going far. But when I looked, the reservoir was half full. Also, once it reached operating temp it held steady and was blowing plenty of heat (unlike when the problem started and was getting no heat with temp gauge spikes).

It doesn't seem like this is indicative of rad being bone dry, is it? I'm thinking no coolant would result in steady increase in heat way above operating temp, and cold air through the heater (since no hot coolant getting to the heater core). Am I missing something?
The shop may have done the proper and honest thing, and filled everything for you. I know we used to at the shop I worked at. Plus it needs to be full for a pressure test anyway.
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Old Feb 2, 2011 | 02:40 PM
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Originally Posted by thundaluvin
The shop may have done the proper and honest thing, and filled everything for you. I know we used to at the shop I worked at. Plus it needs to be full for a pressure test anyway.
Turns out they may not have been so honest. An update: Went to a different shop for a second opinion (they had looked it over a couple of weeks ago). They found NO LEAKS anywhere in the coolant system; the first shop claimed the rad was "bone dry," which was clearly false (even I could verify that).

The second shop wasn't precisely sure what was causing spikes in temp gauge; they couldn't recreate it, and it hasn't happened since I picked it up from the first shop. Replaced therm and temp sensor to rule that out; I have a feeling the water pump could be going. We'll see...thanks for the tips.
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Old Feb 2, 2011 | 03:23 PM
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how do you service the radiator if there isn't a radiator cap
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Old Feb 2, 2011 | 03:25 PM
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what do you mean by service
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Old Feb 2, 2011 | 04:04 PM
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Originally Posted by thundaluvin
Most of the time the water pump will leak before it fails completely, but not all the time. yes when replacing rad an water pump I would replace t-stat as well. I would also back flush the heater core at the same time.
I always reconmend replacing the Tstat when ever I am working with coolant, it is relitivly cheap to replace and you knock that in one shot to give yourself a better feeling of security the everything is new.
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Old Feb 2, 2011 | 05:21 PM
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IIRC, +/-$250 will do the entire cooling system, parts wise.
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