Where is this antifreeze from? It's accumulating on the driver's floor mat.


Asked by Nov 09, 2013 at 03:37 PM about the 1997 Cadillac Seville SLS

Question type: Maintenance & Repair

I have had a slow leak that has just this week turned into a significant leak of antifreeze coolant. It pools up on the driver's side mat. I always wondered why the mat was damp, but now it is actually WET.  I was getting a "Low Coolant" message about once a month, so I have just been filling it with distilled water to top it off. Now I am really concerned though because I cannot locate the exact source of the leak. All I know is that it accumulates on the driver's side floor mat. Any clues what this might be? I believe the heater core is on the other side... Thanks in advance, Chris.

5 Answers

Tom Demyan

Since your low on coolant and no leaks in the engine bay, it very well might be the heater core, and the fluid is migrating over to the driver side. But perhaps the A/C evaporator drain is plugged and the water has no where to go but your floor. There should be a small tube under the car near the firewall take something stiff that will fit in that tube and rod it out and see if its plugged.It will be under the car, near the firewall on the passenger side.

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Best Answer

A new twist: About a week ago, when this really became a serious leak, I blocked off (with plexiglass) an opening under the hood that I thought looked suspiciously like something had been there before covering a 3"x4" opening in the casing unit for the heater fan housing. Hot air was blowing straight out of this opening. What is this opening for? Through the opening, I can see the heater core (I think -- it looked like a mini radiator). Was it some sort of ventilation/filter thingy covering this outlet before? If so, blocking it off was, in retrospect, a bad idea! And maybe it has something to do with the leak getting way worse in my car. The timing is right. Previously, I only had a little moisture being lost from my cooling system (about a pint a month), and it certainly wasn't enough to accumulate on the floor like is has been this past week.

Tom Demyan

You shouldn't be able to see the heater core, which is the mini radiator as you describe it. There should be a panel or maybe even a blower motor that should draw air in from the outside to inside your car, not blowing the other way. You need to find the part that is missing and fix the replace the heater core. Can you post a pic so we can help further?

2 out of 2 people think this is helpful.

First determine if the liquid is water or antifreeze... touch your finger to it, if it's colored red or yellow it's antifreeze. Assuming it is, it's coming from the heater core, a connecting hose or pipe, or a seal on the connection. Get access to a shop manual or google "replace heater core 1997 seville" and take it from there. After fixing the problem, plan on flooding that floor area several times with water and a very small amount of carpet or clothes soap, and use a shop wet/dry vac. If the carpet can be easily removed for cleaning it's much easier and more effective. That crap is sticky ang greasy and is a pain. Good luck.

Chris Davies

Log time, no post. So here's the update: I took it to a mechanic and he said that the leak is probably from my water pump (some kind of overflow valve?). By his estimation, I have a blown headgasket! That bummed me out for a few weeks, but now I think I have a plan. Since (I've) heard that i if you see water on the dipstick when you take it out, it has a headgasket leak. In fact, it didn't seem to be leaking from there anyway -- it seemed to coming from my water pump. First I replaced the thermosts since that was easy. My next task is to replace the water pump. EEeekk! Also of note: there ls pressure built up in the coolant system after just 10 seconds of running it. Then in quickly overheats and auto-shutdowns. So unless anyone has any other ideads. I will replace the water pump for you (or you could have it done professionally.

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