Coolant leaking, overheating, cab heat not working...

[DrivesLikeAGirl]

I know that's a tall order of things going wrong.

To sum up, my 2003 300m started overheating early/mid fall. It was rather random but usually coincided with me being stuck in rush hour traffic. Right before Thanksgiving, I had the oil and fluids checked/changed and the shop told me I was 2 quarts down on the coolant. They said they found a leak but couldn't identify the fluid. They thought tranny fluid, but I was doubtful given that the transmission was re-built last winter.

The overheating issue went away but as the weather changed, I noticed that the car took forever to heat up on cold mornings. Or rather for the first few cold mornings that I used the heat. After the coolant was filled, the car was operating normally.

Well Saturday, the car started overheating again. My stepdad checked the coolant and put what he had left in a bottle (which wasn't a lot). I drove the car on Sunday with no overheating, but the cab wouldn't heat up. It was freezing cold on the way to work yesterday. When I started home, once again, the heat wouldn't come on but then the car started overheating. I finally made it an auto parts place to get some coolant where we discovered the reservoir was bone dry. We put some in and it was immediately siphoned out. We let the car cool down completely and put more in and it maintained the levels. I traded out cars with my folks so my stepdad could take a look today after work. The car has been in their driveway since last night. My mom just called and said that there was a puddle all under the car.

Sigh.

Is this just a cracked hose, possibly the thermostat or is it something more serious like the water pump? What kind of cost am I looking at (roughly)? You guys alway steer me right so I thought to check here before I go through the expense of changing a bunch of stuff that might not be the problem.

Thanks in advance!

[Brando26]

Personally, I just experienced a cracked side tank on my oem radiator. It was on the passenger side. I was leaking a couple dots of fluid before hand and couldn't figure out what it was until it was too late and I overheated. You won't get heat in your car if there isn't a high enough level of fluid to make it up into the heater core in the dash. Our hoses generally don't crack, but that doesn't mean you shouldn't check them anyway. Do a pressure test and look for the leak... You'll know where to go from there. If its water pump you should be losing the fluid around the bottom of the timing cover around the crank pulley

[DrivesLikeAGirl]

Thanks Brando.

We just had the car towed to the shop. My stepdad was hesitant to drive it anywhere with the coolant not staying put. I guess I'll know the damage tomorrow. How much was your repair, if you don't mind me asking? Or did you do it yourself? I wish we were more mechanically inclined.

[FIREM]

Kind of sounds like low coolant is both your no heat in cabin and overheating. At 150+k may be a radiator
Have the shop find the leak source and take it from there. Rad cost plus mark up and installation could be around the $500.00 mark.
If the timing belt and waterpump have not been done get a price for that now !
Make sure whan all is said and done the cooling system is flushed and the proper HOAT Coolant is used.

[DrivesLikeAGirl]

Kind of sounds like low coolant is both your no heat in cabin and overheating. At 150+k may be a radiator
Have the shop find the leak source and take it from there. Rad cost plus mark up and installation could be around the $500.00 mark.
If the timing belt and waterpump have not been done get a price for that now !
Make sure whan all is said and done the cooling system is flushed and the proper HOAT Coolant is used.

Fabulous. We do need the timing belt and water pump replaced. We just didn't have the money to do the 100k service when it came due. Might not have the money now if there's a $500 repair in our future. So maybe this is a case of hoping that it is the water pump. The lesser of the two evils, perhaps?

[Maximus]

your 75,000 past the first timing belt maintenance. You might as well wait until 200,000 for the next schedule change, just joking... my guess is the radiator is bad. I also guess at this point you dont have the correct coolant in it. You probable have a mix of green in there.

[300maximilien]

Cracked coolant overflow tank is a good suspect as well

[02sxt]

I think it might be the water pump. If it is, get that timing belt changed as well. Also get the proper coolant, Zerex G-05, I find it at NAPA.

[Brando26]

My rad from autozone is a spectra brand. Supposeduly last longer than the ready rad from advance auto. It cost $140 plus the price of coolant and $180 in labor. So close to 400 because I bought and delivered the part and avoided the parts upcharge.

[grayslater]

Cracked coolant overflow tank is a good suspect as well

X2 on this but the 100K maintenance is way overdue!! I hope you overheating events weren't too frequent or long lasting?? Potential cylinder head problems as a result?

Kind of sounds like low coolant is both your no heat in cabin and overheating. At 150+k may be a radiator
Have the shop find the leak source and take it from there. Rad cost plus mark up and installation could be around the $500.00 mark.
If the timing belt and waterpump have not been done get a price for that now !
Make sure whan all is said and done the cooling system is flushed and the proper HOAT Coolant is used.

Also as Bob has mentioned, with all the mixing on coolants, a proper flush of your cooling system is in order. HOAT not OAT!

[user97]

100K t-belt, water pump replacement should be done ASAP -- if the pump/belt breaks the engine will be SEVERELY damaged, probably necessitating scrapping the car/swapping the engine.

Would strongly recommend performing the work.

[DrivesLikeAGirl]

Thanks all! I just got the diagnosis and like many of you predicted, the radiator was cracked. And FireM, you were dead on with that estimate: it's going to be $510 including the system flush and appropriate coolant. Although I'm going to call back and make sure they use HOAT.

This question is slightly off the coolant topic, but they also told me that my rear brake pads needed to be changed. They said that they were at 0% and that the brake system needs to be flushed. Is this true?

I will see about getting the timing belt changed ASAP too.

[300maximilien]

At your car's mileage and age it is not a bad idea to flush and refill your brake system with DOT4 fluid. Brake Fluid tends to hold moisture. It is a very easy process and they should not charge more than 1 hour of labor IMO plus fluid. I would even be tempted to negotiate it as a courtesy with the rear brake service.

Did you take their first offer on the Radiator quote? I would ask for a discount.....I'm a negotiator.....just because.....cash discount....combined with brakes....ETC ETC

[FIREM]

Sorry to be right but we do know our M's here.
Brakes are a safety issue,get them repaired. If you have even a little know how there are loads of help topics on the site to help you save a few $$ Fluid flush recommended at time of brake job. Again easily done.
Timing belt is a hand grenade with the pin out if it was never done.
Club members have been guided thru thiis job also.
Search around the site, loads of good stuff...

[Maximus]

at your mileage its probably wise to change out the rotors also if you never changed them.

[user97]

I would strongly advise doing t-belt AT THE SAME time as the radiator -- the reason for this is simple -- huge labor savings.

Upper radiator cross member, fans HAVE to come out both for the T-belt and the radiator replacement job. Coolant (HOAT) is expensive -- with shop mark ups you are probably looking at $50-70 in coolant ALONE -- coolant will need to be drained for T-belt/water pump replacement.

Especially combined with rear brakes, you are looking for a potential to negotiate a much better deal then if you were doing t-belt alone...

A highly questionable water pump (due to age) is now in more questionable shape due to overheats -- you are going to run the risk of ruining the engine RIGHT after having put in money for radiator replacement.

[Bill Putney]

...I'm going to call back and make sure they use HOAT...

Sorry to be repetitive, Caroline, but don't just tell them it must be HOAT. Some people - even professional mechanics - may not know the difference and think "Hey - it's only one letter difference - HOAT - OAT - must be the same thing". I would tell them HOAT, which is also G-05, but also emphasize *NOT* OAT which is also called DexCool.

[beespecial]

MAINTENANCE, MAINTENANCE, MAINTENANCE! If a car is not maintained properly and on schedule it WILL leave you stranded, injured or worse. Doesn't matter what kind of car someone owns, it must be maintained if the owner expects it to be dependable and safe. If you can't have the radiator, brakes and TB/WP all done at the same time, you have to do at least the brakes and radiator now, with the TB/WP very soon after. It does you no good to have it go if you can't stop. That is a lot of cash to lay out to fix a car that is barely worth twice the repair costs, but what's your safety and time worth?