Community Forums

rvtodd · 08-05-2012, 06:34 PM

Very newbie here.We took our 77 dodge on the road for a few test runs.Just to get used to driving it mainly. For a couple of hours or so. .My dodge has a chrysler 360 rebuild with 45,000 miles. When we got home from first trip, I checked under rad saw small antifreeze drips.Popped hood ,traces of antifreeze on right side of rad,along seams.My mechanic suggested trying some stop leak, so I did. Second test trip went good ,got home checked all levels and no leak.Went for another test trip yesterday.This time took motorhome on faster highway.Reached destination ok.Popped hood everything seamed fine. Headed home same highways.After backing in motorhome into driveway, shutting down engine, a noise was heard. My radiator sounds like it was boiling, like a kettle sounds.The hood was extreamly hot to touch.Found a towel and opened latch after about 15min of cool down.The overflow tank was about 3/4 full.Normally has 1/4 in it. Now mind you this last trip was done on a very hot day, 33 c and high humidity.But still think something is wrong here.Next day after the engine was cooled, overflow was back to 1/4 and took of rad cap, level was full. My neighbour says check the rad cap spring and seal, may not be pressurizing system.When running engine in driveway with cap off at operating temp, level is staying full. Anyone know what may be happening here?

gauto5150 · 08-05-2012, 08:00 PM

Hot day in an older motorhome usually gets you running "hot" a little.
Stop leak is a temporary repair, sometimes it lasts longer than normal. But your core in the radiator may have some blockages causing hot conditions in hotter weather.
Maybe you can have the radiator flow tested.

Midniteoyl · 08-05-2012, 08:05 PM

First things to check are:

If clutch fan, that it is actually working.. replace clutch if in any doubt. They are fairly cheap.

Radiator cap is good. Here, I would simply replace also..

Thermostat is good.. again, I would simply replace..

Water pump is working good..

That your coolant mixture is no more than 50/50 (or 60/40 if need in your northern climate). Water cools better than glycol any day..

rvtodd · 08-06-2012, 05:59 AM

Thanks, I will check into all of the above. Starting with the rad cap.

Dunner · 08-06-2012, 06:32 AM

Don't worry about the stop leak. When I was changing the injection pump timing on my `97 Cummins 10+ years ago, the gear popped off and hit my radiator. I used Alumiseal to stop the steady stream. It hasn't leaked since. If the seam does leak again, and the end caps are plastic, they can be re-crimped.

rvtodd · 08-11-2012, 03:31 PM

Alright. So we checked the rad cap.Seems a little loose or kind of rocks back and forth with hand on top.The seals underneath the cap are not cracked.But to make the cap tighter I took pliers and bent the underside of the cap ,so that the under edge that grabs the rad top is tighter.Now when I tighten it down, it doesnt rock back and forth anymore.Much tighter seal,I think.Also I was told by my mechanic since this MH was not used for a while ,to clean the front surface of the rad,fins.This I did also with a garden hose,and spray nozzle. Then we went on a 40 mile trip this afternoon to test it out.It was 28c and stopped a few times to see if there were any signs of over heating. None were present, and the overflow level remained the same. Maybe this was a problem with this rad.The cap pressure, along with a clogged rad surface. Anyone know if any other problems were present, such as water pump etc. Would the overheating occur again? Or did I get rid of the problem? thanks.