Packard Forum Index » Post-War (1946-54)

I am restoring a 51 Packard Henney hearse for a customer. I inherited this project from another shop and have it reassembled. It is a decently low mileage car with what appears to be the original 327 engine. The current owner bought it at a car show but never drove it. It obviously drove because it was at a car show, but don't know any history.

We took the engine out, cleaned it, painted it, and put all new gaskets. The inside of the engine was very clean. The water distribution tube looks new. We installed a new water pump and everything else new as needed. We installed it and it fired right up. We ran it watching oil pressure, which is good, and the temp. The temp kept climbing and we turned it off when it hit 200. Since then we've tried everything we can think of to fix this problem.

We changed the water pump again, tried a different thermostat, took out the thermostat, had the head surfaced, checked the water distribution tube, put in a very large aluminum radiator, added an electric fan in front of the radiator, built a fan shroud for the mechanical fan, checked timing, richened the fuel mixture, etc. Nothing seems to help. Within about 10 minutes of running, it hits 200 degrees. We can see water running in the radiator so we know coolant is circulating very good. It just won't stay cool. Funny thing is even at 200 you can reach in, turn the key, and it starts and idles like a sewing machine. It even shuts off perfectly. It doesn't act hot at all. I'm out of ideas. Even my engine builder who's done many straight 8's doesn't have an answer. Any idea where to go from here?

If it isn't boiling over, it isn't too hot. The engine needs to run at 180F to 200 F. 210 F is no problem. ***Is the gauge accurate?****

The coolant temperature at the water outlet can be as high as 210 or so with no problem.

A 180 F themostat is usually good for general driving. 180 means it will start to open at or near that temperature.

One thing that could cause actual overheating is a heater core bypass. In some cases, bypassing the heator core with a length of hose will allow too much coolant to bypass the radiator, which might lead to overheating.

TxGoat beat me too it as that's what I was about to say!

As for it being the original engine, I've owned five Henney-Packards with three being in the same era as the one you're working on and they have a different ID plate than the passenger cars. If it's still there, it should have the engine number stamped on it so just compare it to the engine. If it's missing, you can still determine if it's the proper engine even if not the actual original by the engine number. The information is here on this site.

We are shutting it down when it gets over 200 using a laser temp gun at the thermostat outlet, so maybe this "hi temp" is just me thinking it is too hot, as well as reacting to the gauge.

The gauge question is interesting. The gauge is pegged to Hot when the engine over 200. The needle is directly in the middle (between E and M in TEMP) when the engine temp is about 160. Where should the needle be when the engine temp is 200?

The gauges can be inaccurate after 60+ years.

Also, what about the radiator? Original, recorded? Aftermarket?

Others have reported issues with recored or modern replacements that are not at the same cooling capacity as the original.

Only other thing would be engine timing.

200F at the outlet is in the normal range. Laser temp guns can be inaccurate on some surfaces.

As for the gauge, I suspect it isn't accurate. I'm pretty sure it should show near the middle of the gauge face at 180 to 190 F. It should not peg at anything under 212 to about 220F. Non-pressurized systems have a lower high limit. A pressurized system using modern type coolant might show H at 225 to 235 F.

Your gauge sender may be off-spec, or the car may have a gauge voltage regulator that is off spec. A poor ground at the instrument cluster might cause bad readings, or a missing engine to frame ground might affect readings. I'm assuming the gauge is electric.

51-54 would be an electric gauge with the sender a screw-in type into the head. If someone used Teflon tape or thread sealer on that tapered fitting, that could affect the grounding of the sender and throw off the readings.

Doug,

Why not get an analog temp gauge from an auto parts store and install it in place of the current one? That might be the best way to remove the ambiguity on this issue. Read the temperature from there and compare it to the expected temperature.

As TxGoat mentioned: is the heater core bypassed?

You can just plug the outlet to the heater core and the inlet at the pump side, correct? My understanding is these cars weren't always sold with heaters in the first place.

200 is not a cause for worry.these engines tend to run hot.i agree if it isnt boiling over youre ok.