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nuisance coolant leak


stixboy

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how's it going, i'm new to the site and just trying to keep my girl running good. i've had this blue 91 caddy deville for 5 years now, though the last two it's been sitting in the garage. pulled her back out bout a month ago, replaced the water pump and been driving her about 70-100 miles a day last three weeks. 3 days ago i stopped somewhere and noticed a lot of antifreeze coming out from under the car, not under the water pump but more towards the inside of the engine. let it sit that night, next day drove it couple of miles and there was no more leaking. no leaks for three days or so and now the leak is back. it's not as bad as before but still something i'm worried about. anybody got anything?

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Borrow a cooling system pressure tester from Autozone and pressurize the cooling system to 15 psi and look the entire system over for leaks. The nice thing about the cooling system pressure tester is you can get the system up to operating pressure (15 psi) while the system is cold so you can inspect the system for leaks without getting burned by hot engine/exhaust components.

The 4.9 engine requires the use of the cooling system sealer (Bars Leaks golden seal, NOT the aluminum sealer). When you replaced the water pump and changed the coolant, did you install the sealer in the radiator?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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You might want to tighten all those bolts around the water pump. After a few weeks, the gasket starts to compress and the bolts need to be retorqued. Also, tighen all hose clamps. Rubber compresses as well.

Borrowing the pressure tester from Autozone is an excellent tip.

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Actually, i didn't add the bar's cooler pellet stuff, or any type of pellets to it ever. i've only got it flushed twice since i had it there past five years. the first time was done at an oil change place. they didn't suggest the pellets so i didn't think anything of it. the second time it was done was when i changed the water pump a couple weeks back. so where should i add them and do i have to do another flush to add them? new coolant and everything? and what exactly is the best stuff to add?

Edited by stixboy
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so where should i add them and do i have to do another flush to add them? new coolant and everything? and what exactly is the best stuff to add?

See post #2 in this thread.

No need for new coolant since you just changed it with the waterpump R&R. Add them to the radiator - you will need to crush them up if they are the pellet type.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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alright guys, sorry i took so long. but about two weeks ago i tightened up all the hoses and i've been leak free from that time on. i've been checking my antifreeze level frequently, both in the coolant reservoir and the radiator. I'm starting to think that maybe i'm using a little coolant at least every 4-5 days. 70 miles a day. only about a quarter inch to half inch in that time. i don't see leaks so i don't think it's coming out. i'm not overheating, no coolant lights on in dash. no oil in coolant. so i'm thinking it's not head gaskets or anything. i don't have the digital dash so i can't check coolant temperature. does anyone know how to check the coolant temperature by the way? so two questions.

how could i be using coolant?

can i check my coolant operating temperature somehow on a 91 sedan deville 4.9 v8?

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Look at your radiator end tanks, for white residue, they crack and it comes out under pressure

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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The tiny cracks on the plastic side tanks open up when the engine is hot. Drive around the block, stop, open the hood and look carefully for leaks and traces of coolant on the ground.

The saddest thing in life is wasted talent

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