1999 Chevy Malibu - locating coolant leak
January 12, 2017 8:18 AM   Subscribe

I know it's leaking, I just don't know from where.

Car was running a little hot. Not a lot, but a little higher than where it usually stops. Checked the coolant, found it nearly empty. Filled it, ran errands. Three hours of errand-running and it was overheating again. Managed to get it home, checked the coolant... almost empty.
The car's worth about $17. It's old, it has additional body damage. It still runs well, though (aside from this coolant issue), and it's our only car.

A) I have basically no mechanical aptitude. How can I mitigate expenses? What can I check myself? What am I looking for? How can I tell if it's something relatively easy like a hose issue VS something larger (aka not home-fixable for someone like me)?

B) If I have to get this serviced, what are some ballpark costs for likely fixes? Arkansas, USA.

C) At what price should I balk at the cost of repair? I recognize that there is some wiggle room here given that it's our only vehicle currently, but at what price would y'all call the car a loss and acquire a different one?
posted by radiosilents to Technology (8 answers total)
First thing I'd do is refill the coolant and start the car running then lie down and look for dripping. That's a heck of a leak so my bet is it'll be obvious. A car that age could just have a worn out hose and that's, generally, a simple, cheap fix.
posted by sixfootaxolotl at 8:28 AM on January 12, 2017 [1 favorite]

Do you smell a burning, fishy/popcorny/plasticy smell? That would be coolant dripping on the engine and burning/evaporating. If you look at the hot engine while running, you'd see a little white smoke, too.

As axolotl said, you should be able to see a drip if it's disappearing that fast -- maybe lay down some newspaper so you can line up exactly where it's falling at.

Also check the oil dipstick; if there's something cloudy/clotty/non-oily on it, you may be leaking coolant internally. If you were losing that much coolant internally, you'd have a lot of other problems, though.

Culprits are either a seal or a broken hose; where the drip falls on the floor may not be directly below where the leak is, because if it's an engine gasket the drip may run along various edges before falling on the ground. Generally, there's a big hose at the top and bottom of the radiator: if these are cracked or damaged, they're good leak culprits.

I know minivans and SUVs do, don't know about a car: does your car have 'rear' heat that is controlled separately from the front? Minivans I've owned will spring leaks along the path to the rear heat core, so it might not come from directly under the engine.

Also, check your floormats: if it's leaking at the internal heater, you could have coolant on the floor of the interior.

As I'm thinking about it, internal heater is probably the place it's happening: it routes engine coolant through a heater core which blows into the car's interior. If you haven't had your heat on for a while, those hoses may not have been under pressure for a while, and if they've deteriorated now when you've been running your heat more the pressure of the coolant may have broken through a weak point. It's happened to me before (the aforementioned rear-heat leaks always seem to happen shortly after running heat for the first time in the fall).

Edit: gaskets and hoses are relatively easy and cheap replacements, probably in the couple-hundred dollar range. If it's a radiator hose and you're handy with a screwdriver, you might be able to replace it yourself for about $50. If it's something like the heater core, head gasket, or a damaged radiator, though, it could get very spendy.
posted by AzraelBrown at 8:50 AM on January 12, 2017 [1 favorite]

You could try using a bottle of leak repair. Follow the instructions on the bottle. It's really easy, might work, might not, but it's way cheaper than your other options.
posted by gregr at 8:56 AM on January 12, 2017 [1 favorite]

Sadly a coolant leak that you can't see, especially one so large, is often internal. IE: head-gasket or cracked block or head that is allowing coolant to leak into a cylinder or allowing exhaust gases to pressurize the coolant system forcing coolant out of the the overflow on the reservoir tank. Unless you can change it yourself it is rarely worth the cost of repair on a beater.

How are you checking the coolant? Just by looking in the reservior tank? Because a tiny leak that emptied your coolant system over the course of weeks will quickly "drain" the tank but that fluid is refilling your engine.
posted by Mitheral at 8:58 AM on January 12, 2017 [1 favorite]

UPDATE : The plot thickens.

posted by radiosilents at 2:57 PM on January 12, 2017

Ok so there are acorns in front of your firewall and a stuffed squirrel on your grille cover?

Please clarify!
posted by spitbull at 5:13 PM on January 12, 2017

If the car was warmed up and coolant tank full when you shot that video, I think we can absolve the squirrel from guilt - i.e., that didn't look like much water was getting out.
If the above conditions aren't met, it might be the source.
Squeeze the hose with your hand - does it feel flexible or really stiff? Do you see little cracks in the surface of the rubber when you squeeze it? If so not good. If it is still flexible, tightening the hose clamp might close that one up.
Check your tailpipe after the car is warmed up on a proper level of coolant in the reservoir. Is there water or steam coming out? This would point to an internal leak.
(full disclosure, I just had to put down my 16 year old truck due to a blown head gasket or cracked head. Oil looked like a chocolate milkshake, water coming out of tailpipe. I haz a sad.)
posted by rudd135 at 5:14 PM on January 12, 2017

If it's low-empty after three hours of errand-running and you didn't notice a giant puddle under your car at some point, I'm pretty sure your head gasket is toast and your coolant is coming out your tailpipe (the previously mentioned internal damage). Turn your car on and stick a paper towel (or your hand) in the exhaust, you should collect a fair amount of moisture. A compression test ought to indicate which cylinders are affected too.

There are some products you can run through your motor that can help prolong your vehicle (try head gasket sealer on amazon) but the proper solution is to remove the cylinder head(s), have them planed and/or rebuilt, and replace the head gasket. Which is usually not worth the time and probably not worth the money if you aren't doing it yourself.

Sometimes the sealant stuff can work for a very long time. I'd be shopping for a replacement vehicle (assuming you confirm this diagnosis).
posted by polyhedron at 6:25 PM on January 12, 2017

« Older It's passive aggressive only if you're in the West   |   Help a kid science the speed of sound Newer »
This thread is closed to new comments.