2005 LeSabre Limited: coolant leak - I need input, please

DrivenDaily

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2005 LeSabre Limited
2005 LeSabre Limited with 205,ooo miles.

When I bought it 7 months ago, I noted a coolant leak but the 'famous last words' now seem to be true: "it never seemed too bad, but now it's worse!"

Recently we've had some really cold days, some of them ranging from 0°F to 10°F overnight. It started with the occasional smell of coolant inside, but no signs of wet carpet (leaky heater core) or coolant on the ground at the fire wall (leaky hoses). Last week on the way to work, even with the HVAC temp set to 90°F, I could barely get any heat inside the car. At least the temp gauge registered in the middle, so the engine seems okay. I added nearly a gallon of coolant and it was better for a while.

Today I made a trip to town, about 15-20 miles each way, and there was just no heat inside again. I bought a new 16 PSI cap and 2 gallons of pre-mix and removed the old 15 PSI cap. I added 1 whole gallon to the reservoir. As I opened the 2nd gallon, coolant was flowing into the radiator. When it got to the top I put the cap on, then added a little more coolant to the reservoir.

I inspected under the hood when I got home. I can smell the sweet odor of coolant and see a very small bit of steam rising from the area between the water pump and firewall.

It still has the plastic elbows, so I'll get some metal ones coming.

The only experience I have with the 3800 is what I've read on this forum. I'm very capable of doing the work needed, but I would appreciate your thoughts on what might be the most likely suspect(s).

Thank you for taking the time to read this and respond!
 
2005 LeSabre Limited with 205,ooo miles.

When I bought it 7 months ago, I noted a coolant leak but the 'famous last words' now seem to be true: "it never seemed too bad, but now it's worse!"

Recently we've had some really cold days, some of them ranging from 0°F to 10°F overnight. It started with the occasional smell of coolant inside, but no signs of wet carpet (leaky heater core) or coolant on the ground at the fire wall (leaky hoses). Last week on the way to work, even with the HVAC temp set to 90°F, I could barely get any heat inside the car. At least the temp gauge registered in the middle, so the engine seems okay. I added nearly a gallon of coolant and it was better for a while.

Today I made a trip to town, about 15-20 miles each way, and there was just no heat inside again. I bought a new 16 PSI cap and 2 gallons of pre-mix and removed the old 15 PSI cap. I added 1 whole gallon to the reservoir. As I opened the 2nd gallon, coolant was flowing into the radiator. When it got to the top I put the cap on, then added a little more coolant to the reservoir.

I inspected under the hood when I got home. I can smell the sweet odor of coolant and see a very small bit of steam rising from the area between the water pump and firewall.

It still has the plastic elbows, so I'll get some metal ones coming.

The only experience I have with the 3800 is what I've read on this forum. I'm very capable of doing the work needed, but I would appreciate your thoughts on what might be the most likely suspect(s).

Thank you for taking the time to read this and respond!
Rent a pressure tester to find the leak. Original intake gasket was an issue.
 
Since you see steam from the water pump to the firewall, I would suspect the water pump is leaking from the front seal.
 
Since you see steam from the water pump to the firewall, I would suspect the water pump is leaking from the front seal.
I tend to think that as well.

Rent a pressure tester to find the leak. Original intake gasket was an issue.
Great suggestion! I will look into that right away. If they're reasonably priced, I may just buy one.

I've read that the LIM may be a good suspect. Is that what you mean by the intake gasket? (Sorry, but I write code and I'm accustomed to having to be very specific or the computer does things to the data that ruins my day. 😉)

Might there be any other "known issues"?
 
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The elbows are ordered; due to arrive around the 22nd.

For the water pump, are there any particular brands to stay away from, and are there any favorite brands that just seem to last and last?
 
Of all the brands of water pumps, I have narrowed it down to either Gates for $28 or Melling for $44.

Does anyone have any comment on these two, or on any other brand for that matter?
 
Is it leaking?
By 2005 the Lower Intake Manifold gaskets were of a better quality than previous years. What's more important is has the Upper Intake Manifold been changed with the updated design?
 
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I have no idea. I've owned it only 7 months and about 5000 miles.
 
You're welcome. I've mostly own Bonneville's, found the site very helpful when it was active. It's now a great resource for other shared models
 
You're welcome. I've mostly own Bonneville's, found the site very helpful when it was active. It's now a great resource for other shared models
Bonnevilles were my favorite until 2000-2005. I've owned two Bonnes, a '97 and a '98. I've always preferred Pontiac styling over its sister cars.
 
I read most of that thread, thanks for posting it!

On RockAuto, ATP offers the intake manifold (plastic) for $79, with gasket(s). Interestingly, they have the only one left for almost $550! Not gonna buy that one for sure!

ATP doesn't offer any gasket sets (on RA, that is).

I don't see any evidence of coolant leaking from the manifold or gaskets, but I'm new to the 3800, so I may be missing something that a more experienced owner would know.

Do you guys think it's worth the insurance to do the UIM gasket, the whole manifold, or let it ride for another day?

PS: The Dorman metal elbows are here, and the Gates water pump should arrive Friday.
 
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You'll come out cheaper searching on Amazon for the ATP UIM. The ATP comes with everything necessary EXCEPT the LIM gaskets. You have to order that separately. I would suggest going with Fel-pro for the updated metal framed gaskets.
 
The water pump has arrived!

It came with a metal gasket with the orange rubbery stuff molded into it.

About the only thing I can think to ask is if I need to use any kind of gasket sealant with the one that came with it?
 
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