Hello folks, I'm new to this forum (joined today). My son has a 300M, 2001 model. When he came home today, the coolant was leaking from the radiator (not sure if a hose or crack in the radiator), pass side. Engine was running hot (between mid-mark and red), but was not boiling. Noticed on the asphalt that there was "rainbow colors" in the coolant spill. That, to me, indicates that there is either fuel or oil in the coolant. Does that mean the headgasket blew on us? Car is running fine, except the leak (obviously not driving any more now until we figure out what caused the leak). Is it a big deal to swap-out the head gaskets on a 300M? I've done it on other cars, but only 4-cylinder cars. Any thoughts would be appreciated. Thanks!

 

coolant will make that same color also if the leak is on the correct side the transmission and oil coolers are built into the radiator

 

Unfortunatly this is a common issue with LH cars. Rad tank failures at around 150K are common. Did you change the timing belt & water pump yet. If not get them done while the rad is out.

 

Just changed the belt and pump about a month ago. Had the radiator/fan out at that time to get the clearance. But saw nothing wrong with the radiator then (other than the drain plug, which I changed). Stupid me, should have changed the radiator then. Car has 210,000 miles, so not surprised. Just worried that the headgasket has taken a beating. Looked in the Hayne's book and it looks doable, but PIA to change the headgaskets. Think I will get radiator fixed first and then take car to Car X to do the gasket leak check for $30.

 

Was thinking that's what it could be too. Leak is coming from right hand side, upper portion....very near where one of those metal pipes go into the radiator (i think that's oil?). If that connection is also leaking, then would explain why oil got mixed with the coolant? I'm hoping that I am lucky that's what it is and not headgasket. I don't know if the car ever overheated in the past, we have not owned the car long...has 210,000 miles so who knows?

 

So I did a pressure test on the radiator....for sure, the radiator is cracked. Leaking like a sill at the top left (right next to the top radiator hose). So now have to make choice, buy a new radiator at Autozone or go to U Pull U Pay (they have several Chrysler's) and pay (maybe) around $20....

 

Now I'm a bit confused about the radiator, need some help here. The left hand side (driver side) has 1) lower radiator hose, 2) one ingoing and outgoing hose (I think transmission fluid?) + 1 more hose, attached with like a "crimped" fitting. When I went to Autozone (and also looked at on-line stores), they don't seem to sell this configuration of a radiator. They only have the lower radiator hose pipe and the nipples for the ingoing/outgoing tranny fluid (?), but there is not "3rd" nipple. What is this "3rd" hose that attaches (I'm not counting the radiator hose itself) to the radiator? Can't makes sense of that, if something goes in should it not also come-out. Funny thing is that I cannot find it locally or on-line. I found a used one at a You Pull You Pay, but the nuts on the oil coolant lines (attaches to the right side) were stripped - could not get them off. Any suggestions woujld be appreciated. Thanks! Sorry for the rambling but I don't even consideer myself a weekend mechanic, so I don't know the fancy terms for all these components and hoses, etc. (sorry).

 

The right side tank has a tendancy to crack as this is where the "hot" coolant from the engine enters the plastic tank. Common failure is cracked tank or seperation at the plastic to aluminum core joint. Strongly advise against salvage yard radiator, has been subject to same heat/cool cycles and will crack at some point in time. New replacements common at auto parts stores and on line.
2001 has an engine oil cooler in the right side tank.
Left tank has transmission cooler lines. Additional lines that wrap around the front of the radiator go to a power steering cooler and an additional trans cooler. Look carefully the additional line you see goes around to the front. There is a bolt clamping the lines to the side of the radiator making it look like the line enters the rad but it does not.
Best bet is to remove the front bumper cover or "facia" for access to those lines.
A/C condencer also mounts to the front of the rad. 2 bolts in the lower area then lift the top "tabs" out of the holders.

 

This may help :http://300mclub.org/forums/viewtopic...or+replacement

 

FIREM: Thanks! This is great information and explains a lot. I was messing a bit with this evening before it got dark (car is on street, not in my garage), and I started to think too that the two hoses I saw must be going on the side of the radiator - you confirmed it. That link with the write-up was great, very helpful.

I got the fan out and almost the rad too. But i ran into trouble on the right side (pass side), the upper oil cooler line nut stripped on me. Could not believe it as I opened that just a month ago when I changed the timing belt. I read in the link that he just cut those lines. Guess I will have to do that too, but how to patch it together again? Will hopefully have the Autozone guys sell me the right components and explain how to do it. I take your advise, and will not go for a used one and spend the $135 at Autozone for a few one. Got a fun packed day tomorrow; fixing my son's Chrysler and then patch-up my Saab 9-5 - chaning the exhaust system and changing the timing chain (real fun stuff!).