Saculia

iTrader: (1)

Hello Everyone,

A couple of days ago I fired up my beloved formula in order to move it from one spot in the garage to another, in order to free up some room.
The car ran beautifully and I didn't let it run long enough, to where the engine got really hot, but it did get over 100 * F, possibly 160. I have a stock temperature thermostat in it.
I shut off the car and noticed that there was a little bit of antifreeze dripping from the bottom of the radiator. Upon further investigation I noticed that the dripping was coming from the radiator drain valve, on the passenger side of the car. It seemed as the coolant was leaking past the seal. The drain plug was tight.
I opened the hood and noticed that the upper radiator hose that goes into the water neck of the thermostat housing was swollen like a balloon about to burst.
I turned the key to the on position without starting the car and noticed the temp gauge reading about halfway between 100 and 220*F. Thus, the engine was not very hot. It had only been a couple of minutes since I had shut off the car. The upper radiator hose returned to it's normal size after the engine cooled off and the coolant leakage stopped.
I suspect that the thermostat may have stuck closed and prevented coolant from circulation. The engine has only had 28K miles since a complete rebuild, at which point a new thermostat and hoses were installed. The car has not been driven as a daily driver since May 2010, other than the occasional starting, running and trip to the gas station to put fuel in it. This has been due to working on body, paint and interior.
The last time the car ran for an extended period of time was 2 weeks ago, when I loaded it up on a trailer for a relocation trip from St. Louis to Minneapolis. There were no such issues then.
I have a few questions about this situations. Could this possibly be due to a stuck thermostat, perhaps due to infrequent use of the car? If so, in addition to the thermostat, should I also replace the hoses and the radiator drain plug on the bottom? Could those components have suffered damage due to the increased pressure that would compromise their integrity later down the road?
All constructive suggestions and answers would be highly welcomed and much appreciated as I am trying to resolve this issue in the next couple of weekends.

Thanks in advance.

naf

iTrader: (7)

A stuck thermostat would not cause an overpressure issue. Fix your leak(s) and any hoses that may be compromised (soft to squeeze or visibly degraded).

When you periodically start it, ensure you let it run long enough for the oil to get above the boiling point of water and for the exhaust to heat up and dispel any liquid water that has accumulated. Water trapped in oil turns into acid and sludge, water sitting in your exhaust rots it out from inside.

Ransford2987

If I saw any radiator hose balloon up I would replace it, even if it were brand new. I would check that the thermostat was installed correctly while I'm at it. As naf suggested, it's probably a leak with the o-ring around the radiator drain plug. I doubt pressure would get high enough to do something like that to the drain, especially if the o-ring is good and the plug is seated tight. Did you notice any other issues? Are all of the other hoses that carry coolant installed correctly or is anything blanked or deleted? If you can't figure it out, try to recreate the problem, then change something, and try to recreate it again.

Saculia

iTrader: (1)

Naf,

Thank you for the suggestions.
I am aware of the damage condensation can cause if not allowed to evaporate from the engine and the exhaust. Thus, whenever I have periodically started the car, I have usually let it run for about 20 to 30 minutes, until the engine has fully warmed up and the primary cooling fan has come on a couple times, prior to shutting the engine off. The exception was this last time primarily due to the coolant leak.

Ransford2987,

Your point is well taken as well. It seems the consensus is that perhaps the culprit of the problem is not necessarily over pressurization, but perhaps a weakening of the hoses and seals.
All hoses and cooling system components have been installed properly and the car has not given me any issues in the past. The engine was rebuilt, including removal and installation, by a reputable machine shop in St. Louis 28K miles ago back in February of 2008. The car has made a few cross country trips since the rebuilt and never had any issues.
The TB coolant was bypassed by the previous owner, but that was never an issue. At the time of the rebuilt, a new thermostat, water pump, radiator and heater hoses were installed. Coolant temp sensor and fan switch were replaced with new ones. Brass freeze plugs were installed at the time of the rebuild. The engine came with a 2 year, 24K mile warranty from the machine shop and has been maintained religiously with Mobil 1 synthetic motor oil 7K miles after the rebuild. The first three oil changes were performed during this 7K mile period with conventional oil. I spent about $5400 on the rebuilt to have this done properly. I also replaced both cooling fan motors and the secondary cooling fan switch that bolts on the passenger side of the engine.

The hoses do seem quite soft when I squeeze them while the engine is not running.
Please advise on the following course of action:
I propose to replace both radiator hoses, thermostat, thermostat gasket, radiator drain plug and perform a cooling system flush. There don't appear to be any debris in the coolant.
Any suggestions on good quality radiator hoses, drain plugs etc. I don't want to put a set of hoses that will weaken on me again in a few years.

Thanks again in advance.

Ransford2987

That's where I would start. Good luck and hopefully it's solved. Keep us posted in the thread.