Re: [Chrysler300] 300G Radiator fan shroud over heating problems
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Re: [Chrysler300] 300G Radiator fan shroud over heating problems

Years ago I bought a North American boat with two six cylinder inboard outboard engines.  It had been sitting, after getting it running, at sea it would overheat, first one engine, then after working on that engine, water pump, cleaning exhaust elbows, etc. the other engine would overheat, then the first, then the second.  I finally pulled the engines and stripped them down, the internal cooling passages were plugged with rust and crud.

I blocked all cooling openings with wood and rubber gasket material and filled the block with dilute muriatic acid.  Left it sit for a while and dumped it out.  Repeated the process a few times then flushed the engines with a water/baking soda mixture.  The cooling passages were clean.  After reassembling the engines and reinstalling them they worked as new, no overheating whatsoever. 

Clogged water passages are not the first thing you think of, but should definitely be considered when all else isn't working.

Bill Huff

At 08:51 AM 10/30/2017, Richard Osborne reomotorsports1@xxxxxx [Chrysler300] wrote:

I wil second Andyâ??s comments. I bought my G coupe almost 18 yrs ago. It had been parked for approximately 20 years prior to my ownership. It ran when I got it, but I changed oil, plugs, etc?. As soon as I did a garden hose flush, I started fighting overheating issues. I had the radiator rodded out, recored, change thermostat, hoses, re-flushedâ?¦. all to no avail. At this point I knew there had to be something wrong internally. As soon as I pulled a cylinder head, this was confirmed. The water passages had barely 1/8â?? hole due to crusty junk being built up in what should be probably a 1/2â?? diameter water passage.

In my circumstance, the engine rebuilder could not get the passages cleaned out with the normal Hot Tank process. They ended up sending my block and heads to Redistrip, the place where they dip entire car bodies to strip away paint and rust. This worked. I rebuilt the engine to stock specs (as far as the cooling system is concerned) and have had no issues. This includes driving across country and back, including through the Mojave dessert at 113F degrees.

This issue is what prompted the entire restoration of that car. I have probably put 40,000+ miles since on the car and have had no cooling issues (other than freeze plugs, which is another story).


On Oct 30, 2017, at 2:34 AM, Andy Mikonis r41hp@xxxxxxxxx [Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

I agree with Keith. These cars worked when new as designed and still will. In my case I battled overheating in my G for years. A new radiator or a proper rodding-out would work for a while. Ultimately it ended when I took my engine to George Riehl for rebuild. He wouldn't just have blocks hot-tanked, but he took them to a place for a shot-peen type process. The block came back looking like a fresh casting. No heating problems since. Point being, you can throw all the fancy radiators you want at your car, but if there's 40-50 years of rust and gunk in the block cooling passages then it won't help. And a radiator shop or garden hose "flush" isn't going to do it.

Good luck!

On Oct 29, 2017, at 11:58 PM, Keith Boonstra kboonstra@xxxxxxxxxxxx [Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:


I have no technical words of advice to offer, but I will be a cheerleader.

I recall a trip of 200 miles I took in my C in the summer of 2016 when the temperature was over 95, the sun was blazing, the humidity was in the 90s, and I got caught in construction traffic jambs. I had put in a recored radiator (of unknown composition) in 2011, I have the factory fan shroud, and everything else in the cooling system is factory except for a temp-controlled fan clutch. I ran my A/C with its big ole RV-2 compressor full-bore that day, but the temp gauge hardly budged over center.

All I'm saying is keep working at it, and stay with the factory setup. Those engineers were pretty good at their craft. Get all of it right and to spec and you will eventually win.

Keith Boonstra

On Sun, Oct 29, 2017 at 10:44 PM, Steve Albu saforwardlook@xxxxxxxxx [Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

I would agree with John, but maybe a 3 row high fin density core would work fine without going to a 4 row if your cooling issues are generally only in low speed traffic.  If you are having issues with higher speed cooling as well, then a 4 row would definitely be advised.  Generally low speed cooling requires a large frontal area and high fin density whereas high speed cooling requires more rows of fins as well.  I personally would go to a reputable radiator shop with my original radiator and have them put in a new high efficiency core. 

On Sun, Oct 29, 2017 at 2:24 PM, John Grady <jkg@xxxxxxxxxxxxxxxxx> wrote:
Second that . Need 4 row core and they cost $!. A 3 row â??rated 4row â?? is not the same . Has to be radiator ? if aall that is new and on correctly? Not sure why anyone would  cut the shroud? It was designed correctly , if the original one? Have to have that right . A front fan should not be needed , all this worked stock without it , and might not help as ac core is a distance in  front of cooling core. Plus it blocks air flow some in center where motor is . Plus they take 20- 25-amp . The car alternator will not like that with Ac system running ,
In Mopar magazine , the one out of New Orleans, someone advertises newly made Mopar radiators including 4 row for restoration , mainly  geared to big hemi etc . But says real  4 row, but almost 1000. I think all of them use similar cores in the large sizes , within # of tube rows .
Big $?  but used or old is a crap shooot ... ??
I had electric , only, on a 480â?? non ac 440, it overheated even at idle . Went back to pump mounted , not finished yet , used a flex fan . ( due to lack of knowledge and cost about various clutch fans and ac fan , which I think has 7 blades, but not sure of that either) . If you have all original ac stuff it should work , if radiator good. Hope this helps

Sent from my iPhone

On Oct 29, 2017, at 4:00 PM, Steve Albu saforwardlook@xxxxxxxxx [Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Having a "new radiator" doesn't mean anything.  What matters is whether you have a core in it that has very high fin density.  If you didn't pay somewhere in the $500 range out the door for it, it doesn't.  Nothing else substitutes for a good radiator.  A standard replacement is junk.  I live in California where temperatures are well above 95F much of the time, so I have some experience with a/c cars. 

On Sun, Oct 29, 2017 at 11:08 AM, thomas tibbie ttibbie@xxxxxxxxxxx [Chrysler300] < Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Hi everyone, I'm back on the same subject over heating on my 300G with A/C, with new radiator, recovery tank and new clutch fan.  I live in the San Antonio Texas area and during the summer months when our temperatures reach 95 degrees + I have an over heating problems. If the temperatures stay below 90 degrees no problem. The radiator shroud  has been cut back so the fan is not covered by the shroud. So I'm looking for radiator shroud that will fit the 300G.  One other question has anyone used an electric fan in front of the A/C radiator to help cooling problems? Thanks     



Posted by: William Huff <czbill@xxxxxxxxxx>

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