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Dreaded low coolant on DIC...


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Good morning everyone,

'99 STS leaking coolant... :angry:

I looked carefully with a flashlight with the car running and stopped.

Lower right corner is wet. Cannot determine where the leak is coming from.

I have read in the archives about some radiator replacements.

There are some other small hose connections there.

Do any of them contain coolant? I know the radiator has plastic endcaps.

Would it be the endcaps leaking for sure? Can I have the radiator fixed, or should I just order one and replace? HELP!

Thanks in advance...

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If you are sure it is the radiator you could probably get one for about $200.00, if I remember right. You can repair it by replacing the end tank that is bad, it is not that difficult. Shop around though, some shops will charge more to fix than a new one costs.

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If the other parts near the hoses are dry, it sounds like the radiator end cap seal is leaking. It's hard to see the exact leak point along the end cap seam with these radiator designs.

I had a crack in the end cap on mine and never saw it until I pulled it out and viewed it in full daylight. A local shop charged me $120 to replace the end cap and seal.

If a shop cleans the radiator in a wash tank after disassembling, make sure they do not use the same tank that is used for brass radiators. It will cause the aluminum radiator to corrode and leak. If they don't have a wash tank for aluminum units, skip the bath and just get the cap and/or seal replaced.

The only other connections are the transmission cooler lines (metal lines on driver's side at the end cap).

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Right - is that the passenger or driver side? if it is the driver side it may be the water pump. I am in the process of getting parts to put in a new pump on the Aurora.

If you remove the lower splash shield and put the car on ramps, you should be able to view the pulley side of the pump when the car is running.

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Thank you Paul T & MayDog,


Thank you for the reply...

The area, lower passenger side, is quite wet.

Looks like the coolant is showing up on the bottom

of the radiator including a small line with clamps

that is present. I don't have my manuals here,

but I wonder what other line is there, that might be leaking.

I don't have a problem replacing the radiator with a new

one, I just want to be pretty sure because I will have to order

it and have to have the car fixed in one day, Saturday.

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I pulled the upper radiator hose on Sunday and added one tube of gold seal

tablets. Monday drove the car 35 miles total and checked the leak. Almost

totally gone...

It was too dark to get a pinpoint, but it looks like it might be at the generator

inlet coolant hose. Looked like everything else was dry now, but that area around

the inlet.

I replaced the front motor mount about two months ago without removing the

radiator. I know we had to tilt the radiator quite a bit to get the mount out/in.

I'm afraid we might have cracked the plastic endcap where the generator inlet

hose attaches.

I don't know if the plastic radiator is cracked or if the hose is bad. I want to order

a radiator now if it is the radiator. Any suggestions to nail it down?

thank you,

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