Temperature and oil pressure 440ci

[Patrick Slegers]

Hello,

Today I made the first ride of this year with my 72 Imperial.
What do you think of the temperature and the oil pressure? The temperature gauge first goes to halfway and then drops down again. The oil pressure seems a bid too high, or is this normal for a 440ci with almost 90.000 miles on it

?

Patrick

 

[68PK21 440.6bbl]

Looks fine via the dash, if your worried about the accuracy you can install manual gauges.

 

[SPF Required]

I never trusted the gauges on my dash. It is in need of restoration. I am giving the tech a try:
EngineStat. Bluetooth connection to your phone. Should have it up and running in a couple of weeks.

 

[CBODY67]

From what you describe, the temp gauge is acting about right. If the small "over-shoot" on the temp gauge worries you, then drill a small hole in the flange on the thermostat. What does it read at 60mph?

The oil pressure should not be an issue, as long as it isn't too low. On many of the cars I've seen with an oil pressure gauge, at idle it's usually at the 1/4 scale mark, then goes higher as rpm increases. Depending upon the weight of oil you're using, PLUS how far you've driven it, those can affect it too. It usually takes about 10 miles of highway driving for the oil temp to approach coolant temperature. Where does the oil pressure go with engine speed of about 2000rpm (or "road speed")?

CBODY67

 

[68 4spd Fury]

Engine warming up until thermostat opens. It might be sticking or wrong temp. Oil pressure is fine I'd say.

 

[Davea Lux]

If the fuel gauge is reading accurately, most likely you are getting good voltage to the rest of the gauges. Both the temp and oil gauges with the readings shown are within normal parameters. If you are worried as to the accuracy of your oil and temp gauges, put a thermometer in the coolant once the engine has warmed up and the thermostat is allowing coolant to circulate. You reading should be about the same reading as the thermostat. If you have a thermostat that is OEM or a same rated temperature, your gauge should at about the middle of the operating range as shown by the solid line at the center of the gauge. Most cars this age have had the thermostat replaced and often folks replace them with a lower temp rated unit. I would pull the thermostat and check the bottom of it for the temperature that it is rated at to see if it is correct. An engine with a "cold" thermostat will often have higher than normal oil pressure because the oil viscosity has not been sufficiently reduced by normal operating temperatures. Oil that is running too cold is more prone to forming sludge because contaminants are less like to be dispersed out of the oil at lower operating temperatures.

Dave

 

[stubs300]

My old tired /6 in my van always seems to read higher until the motor gets good and warm, then it drops to about center while driving and lower at idle. Good Luck

 

[PontiacJim]

Hate to say this, and I'm not knocking Mopars, but it has been my experience that the gauges don't work so good as they get older.

On my '73 Fury (w/AC so big radiator/fan in it) the temp gauge reads mid temp but doesn't take much for it to go past mid temp and on a hot day in stop/go traffic it begins to creep up 3/4 and uncomfortably a tad bit more if I let it, looking to go into boil over mode. In stop/go traffic I would throw the trans into Neutral and rev the engine slightly to bring the temp down away from the danger zone (which the factory drivers manual suggests) Went through all the usual stuff changing things out and still the same readings.

Finally purchased one of those hand held laser temperature guns to see if I had any hot spots in the engine, radiator, or cooling components. Lo and behold, my gauge still showed past the mid mark and my temps using the laser gun showed 160 - 170 degrees - which is pretty darn good in my book.

So it would seem the gauge/sending unit or some other issue is the culprit for the higher than normal reading on the gauge.

Also, speedometer does that bouncing around all over the MPH range when cold, but settles down once it gets warm. My brother's 260,000 mile '73 Plymouth does the same thing. I just live with it when it happens, but have had other Mopar cars do the same thing.

Agree with everyone on the oil gauge, looks ok, but you really don't know its accuracy without a mechanical gauge to monitor the pressure. Oil viscosity and engine temps can make a difference in the reading as well.

Another thought is, and some of you can help me out here, is that the Mopar engines have their timing somewhat retarded so they run hotter in an effort to produce better emission readings. I am not sure when in the early 70's this began, but I read my '73 has all that emissions stuff. I advanced my timing a bit and it seems to run a little better, but it may be all in my head.

 

[Davea Lux]

Hate to say this, and I'm not knocking Mopars, but it has been my experience that the gauges don't work so good as they get older.

On my '73 Fury (w/AC so big radiator/fan in it) the temp gauge reads mid temp but doesn't take much for it to go past mid temp and on a hot day in stop/go traffic it begins to creep up 3/4 and uncomfortably a tad bit more if I let it, looking to go into boil over mode. In stop/go traffic I would throw the trans into Neutral and rev the engine slightly to bring the temp down away from the danger zone (which the factory drivers manual suggests) Went through all the usual stuff changing things out and still the same readings.

Finally purchased one of those hand held laser temperature guns to see if I had any hot spots in the engine, radiator, or cooling components. Lo and behold, my gauge still showed past the mid mark and my temps using the laser gun showed 160 - 170 degrees - which is pretty darn good in my book.

So it would seem the gauge/sending unit or some other issue is the culprit for the higher than normal reading on the gauge.

Also, speedometer does that bouncing around all over the MPH range when cold, but settles down once it gets warm. My brother's 260,000 mile '73 Plymouth does the same thing. I just live with it when it happens, but have had other Mopar cars do the same thing.

Agree with everyone on the oil gauge, looks ok, but you really don't know its accuracy without a mechanical gauge to monitor the pressure. Oil viscosity and engine temps can make a difference in the reading as well.

Another thought is, and some of you can help me out here, is that the Mopar engines have their timing somewhat retarded so they run hotter in an effort to produce better emission readings. I am not sure when in the early 70's this began, but I read my '73 has all that emissions stuff. I advanced my timing a bit and it seems to run a little better, but it may be all in my head.

One of the reasons that A/C equipped mopars tend to have the temperature creep up at idle is because the clutch fan has failed or is failing. Try shutting the engine off after the car is fully warmed up. If the fan spins freely after you shut down the engine the clutch fan is shot. (a bad or missing fan shroud will cause the same problem) Most mopars will pull enough air thru the radiator at highway speed to keep from overheating, the problem occurs at low speed or at a stop because with a bad clutch fan no air is being circulated thru the radiator. Temp sensors do go bad. If yours is a 50 year old OEM unit, you should probably replace. Repop units are still readily available.

Most of the timing settings from '72 onward were calibrated to reduce emissions. and did little for performance. Try using a vacuum gauge to set the timing. Hook the gauge into manifold vacuum and adjust the timing to get the maximum amount of vacuum possible on the gauge. You should get a significant improvement in performance. You might have to fatten up the idle mixture settings and the metering rod settings as advancing the timing may make the engine run lean. These settings including timing should be adjusted with the engine fully warm. Your '73 has a low compression smog motor so don't expect miracles, but the above procedure should help.

Dave

 

[CBODY67]

When my parents got their new '72 Newport Royal 400 2bbl, I was surprised to see a 185 degree thermostat (factory) spec for it, in a time when GM had been using 195s for several years. I thought that was good. But most were probably replaced with 180s later on. I don't think they went to the full 195 degree thermostat on the C-body cars until '74? Timing was set to 7.5 degrees BTDC, but interestingly +/- 2.5 degrees. That was on the emissions/tune-up decal under the hood! Those things told me that Chrysler was pretty close on their emissions output so that they had that much lee-way with the timing settings and didn't need the hotter thermostats that GM and Ford had to have. That low-compression 400 ran pretty good, compared to the '66 383 2bbl in our '66 Newport . . . all things considered.

"Creeping heat" is not unique to Cnrysler products! With the GM cross-flow radiators, it can be a sign that the lower cores of the radiator are somewhat sedimented (i.e., no flow). An infrared heat gun thermometer can quickly indicate that.

There WAS a TSB about elevated engine heat in stop-go traffic on the '72 Chryslers. My parents' '72 got that recall/campaign modification. Seems that in hot traffic, the air going through the radiator would be blown forward and "recycled" through the a/c condenser and radiator again, resulting in higher underhood temps AND could elevate enough to raise the a/c head pressure enough to pop the a/c hoses.

The TSB items included flat rubber sheeting, die-cut, to go on the valance panel and the side braces for the headlights, and possibly inspecting the weatherstrip on the underside of the front of the hood, which sealed against the upper radiator area. That ensured that all air coming into the radiator came from the grille area, rather than from under the car. There was also a TIC (thermostatic ignition control) thermovacuum switch that went in the new thermostat hBuousing. When coolant temp got to a particular "higher" level, it switched the vacuum advance vacuum from ported to manifold, to increase the engine speed slightly (for more rpm of the cooling fan).

So, for good measure, you might look for the flat rubber sheeting. But from what you've mentioned, everything looks decent as is.

FWIW, looking at the top cores of the radiator through the filler neck (with the radiator cap safely removed), all you're seeing (that generally looks decent) is the top few cores on a cross-flow radiator, or the top of the core on the vertical flow radiator. You can't see what's in the bottom of the radiator, which is where the infra red non-contact thermometer gun comes in very handy.

As the coolant sensor grounds through the coolant, the ph level of the coolant can supposedly affect the readings of the sensor. So, as the coolant might look good, it might have a flaky ph level that could cause temp gauge readings to be a little off.

Enjoy!
CBODY67

 

[bajajoaquin]

Might be the thermostat. Years ago I drove a friend’s truck that displayed a similar pattern. The temp would go high before dropping down. Got worse and worse till it blew a head gasket. Turned out that the thermostat was bad. It required excessive heat to open. Once open it would stay open but got too hot before that.

 

[PontiacJim]

One of the reasons that A/C equipped mopars tend to have the temperature creep up at idle is because the clutch fan has failed or is failing. Try shutting the engine off after the car is fully warmed up. If the fan spins freely after you shut down the engine the clutch fan is shot. (a bad or missing fan shroud will cause the same problem) Most mopars will pull enough air thru the radiator at highway speed to keep from overheating, the problem occurs at low speed or at a stop because with a bad clutch fan no air is being circulated thru the radiator. Temp sensors do go bad. If yours is a 50 year old OEM unit, you should probably replace. Repop units are still readily available.

Most of the timing settings from '72 onward were calibrated to reduce emissions. and did little for performance. Try using a vacuum gauge to set the timing. Hook the gauge into manifold vacuum and adjust the timing to get the maximum amount of vacuum possible on the gauge. You should get a significant improvement in performance. You might have to fatten up the idle mixture settings and the metering rod settings as advancing the timing may make the engine run lean. These settings including timing should be adjusted with the engine fully warm. Your '73 has a low compression smog motor so don't expect miracles, but the above procedure should help.

Dave

Yep did all that. The clutch fan seemed a little weak, so replaced it. Noticed fan shroud missing, so installed one. Car has all the rubber sheeting to direct the air. Hoses looked good and no kinks, fan belt tight, etc.. Bumped timing (1973 - 318 CI & 360CI is TDC or 0 degrees) to about 8 degrees BTDC and did fatten up the idle screws a bit. None of what I did seemed to change what I saw on the gauge. Again, engine seems to be running fine and even when it climbs high on the gauge, it is not hot - just the gauge would lead me to believe it was running hot and that's why I finally got the infrared laser temp gun to know exactly what was going on because my next step was to pull the radiator and have it checked. Car only has 59K on it. The 360 pulls pretty strong (even with the 2Bbl) and it has the 2500 RPM factory stall converter so it'll take off from a red light nicely when I nail it. I can feel it fall off as I get into higher RPM's, but it is a good pulling engine up to that point.

So it runs well for what it is. Eventually a HP rebuild will take place in the future, but not until I get some of my other projects out of the way. For now, its a great cruising car.

 

[70bigblockdodge]

Yep did all that. The clutch fan seemed a little weak, so replaced it. Noticed fan shroud missing, so installed one. Car has all the rubber sheeting to direct the air. Hoses looked good and no kinks, fan belt tight, etc.. Bumped timing (1973 - 318 CI & 360CI is TDC or 0 degrees) to about 8 degrees BTDC and did fatten up the idle screws a bit. None of what I did seemed to change what I saw on the gauge. Again, engine seems to be running fine and even when it climbs high on the gauge, it is not hot - just the gauge would lead me to believe it was running hot and that's why I finally got the infrared laser temp gun to know exactly what was going on because my next step was to pull the radiator and have it checked. Car only has 59K on it. The 360 pulls pretty strong (even with the 2Bbl) and it has the 2500 RPM factory stall converter so it'll take off from a red light nicely when I nail it. I can feel it fall off as I get into higher RPM's, but it is a good pulling engine up to that point.

So it runs well for what it is. Eventually a HP rebuild will take place in the future, but not until I get some of my other projects out of the way. For now, its a great cruising car.

My Challenger has the same issue. Everything except the actual guage in the dash has been changed. And guess what, it still reads high. It's not really hot just the guage is out of cal. I have learned to ignore it. My Charger is more fun as they don't work at all. They pop on every once in a while.
To the OP they look fine but a thermostat would not be a bad idea.

 

[CBODY67]

I always liked the gauges with numbers on them, but the "operating range" gauge can be just as well, even if they might be reading a little higher than they ought to be. Gets to be an issue if it's the fuel gauge, though, but once you find the limits, you know how to deal with things. A friend who has had many late '60s-early '70s A-body Dodges claims that they all read a little high on the fuel gauge, such that they ALL (of the ones he's owned) ran out of gas showing a 1/8 tank remaining. In that respect, there's a thread in here on an electronic add-on to fine tune the fuel gauge readings (and to compensate for tank sending units with different resistance values than OEM).

CBODY67

 

[DocMcNeedy]

Mine (72) at start of car trip today backing out of garage after about 30 seconds...I can take one after running awhile. Usually both at midpoint or a little over to the right of midpoint.

 

[DocMcNeedy]

Got this too. Worthless.

 

[PontiacJim]

I always liked the gauges with numbers on them, but the "operating range" gauge can be just as well, even if they might be reading a little higher than they ought to be. Gets to be an issue if it's the fuel gauge, though, but once you find the limits, you know how to deal with things. A friend who has had many late '60s-early '70s A-body Dodges claims that they all read a little high on the fuel gauge, such that they ALL (of the ones he's owned) ran out of gas showing a 1/8 tank remaining. In that respect, there's a thread in here on an electronic add-on to fine tune the fuel gauge readings (and to compensate for tank sending units with different resistance values than OEM).

CBODY67

My gas gauge is just the opposite, fill it up and it reads a little above 3/4 and then drops down from there. Not really an issue as I typically fill it up when it hits 1/4 just to be on the safe side, but it isn't as low as it shows. I don't go far with the car and use it as a summer/good weather car buzzing around on weekends. I have AAA to bail me out if I run into problems. In 16 months of ownership, I've put about 900 miles on it.

 

[Patrick Slegers]

Thanks everyone for your replays, I'm always learning here.

I'm thinking of replacing the thermostat, but does anyone knows which is the correct one to purchase? A member of the Imperial group told me that a 440 needs a 195 degrees thermostat but when I check the 1972 Plymouth Chrysler Imperial Chassis Service Manual it says I need a 185 degrees thermostat.

I think the oil pressure issue is related to thickness of the oil. I changed the oil and for the first time I used thicker oil (Lucas Oil Hot Rod & Classic Oil SAE 20w50). I used to use 10w40, to be honest, don't know why I changed to 20w50.

Patrick

 

[PontiacJim]

I don't think it will matter much on T-stat choice. 10 degrees is not much. I prefer the lower T-stat as it can lower engine temps, but I like to run a 160 T-stat. If you drive in winter/cold weather, then you would probably want the higher temp T-stat so you get good heat out of your heater. Not sure if any emission items that might be found on your car would be tied into the engine's running temps.

If you get a typical store bought type T-stat, I also suggest that you drill a 1/8" hole or two in the T-stat just outside of the center section, but no so far as to get into the gasket sealing edge. I actually drill 3 in my T-stats. The purpose for this is that it will allow any trapped air through and helps in re-filling the system. If the T-stat ever sticks closed, it allows some (very little of course) anti-freeze to flow, but more importantly if the T-stat sticks, the engine can get hot enough to boil the anti-freeze and then blow it back out through the lower radiator hose and out the radiator - rather quickly & violently in my experiences. The small holes relieves this and lets that boiling pressure to escape - and can slow the rate of boil over which is going to happen anyway if the T-stat sticks closed.

Looked up one for a 440CI application and this one by Milodon seems to have good reviews (some others did not): Milodon High-Flow Thermostats 16406

And, here is an interesting post to read which might be of some help (?) as well: Correct thermostat for 440-3?

On the thicker oil, as bearings and other surfaces wear, clearances open up. Lighter oil can flow easier out of the larger clearances whereas thicker oil won't. So it may simply be a sign of wear on the engine. Like the T-stat, not always good to have the heavy oil if you use it in winter/cold weather as the thicker oil when cold can take longer to reach bearings and can put an additional strain on the oil pump/gears when you first start the car to warm it up.

 

[Patrick Slegers]

I don't think it will matter much on T-stat choice. 10 degrees is not much. I prefer the lower T-stat as it can lower engine temps, but I like to run a 160 T-stat. If you drive in winter/cold weather, then you would probably want the higher temp T-stat so you get good heat out of your heater. Not sure if any emission items that might be found on your car would be tied into the engine's running temps.

If you get a typical store bought type T-stat, I also suggest that you drill a 1/8" hole or two in the T-stat just outside of the center section, but no so far as to get into the gasket sealing edge. I actually drill 3 in my T-stats. The purpose for this is that it will allow any trapped air through and helps in re-filling the system. If the T-stat ever sticks closed, it allows some (very little of course) anti-freeze to flow, but more importantly if the T-stat sticks, the engine can get hot enough to boil the anti-freeze and then blow it back out through the lower radiator hose and out the radiator - rather quickly & violently in my experiences. The small holes relieves this and lets that boiling pressure to escape - and can slow the rate of boil over which is going to happen anyway if the T-stat sticks closed.

Looked up one for a 440CI application and this one by Milodon seems to have good reviews (some others did not): Milodon High-Flow Thermostats 16406

And, here is an interesting post to read which might be of some help (?) as well: Correct thermostat for 440-3?

On the thicker oil, as bearings and other surfaces wear, clearances open up. Lighter oil can flow easier out of the larger clearances whereas thicker oil won't. So it may simply be a sign of wear on the engine. Like the T-stat, not always good to have the heavy oil if you use it in winter/cold weather as the thicker oil when cold can take longer to reach bearings and can put an additional strain on the oil pump/gears when you first start the car to warm it up.

Thanks for showing me the Milodon thermostat, only Summit charges very high shipping rates to Belgium/Europe ($40). I also looked at RockAuto, their thermostats seem to be much cheaper, but also poorer quality I guess.

I have a few extra questions related to the post you referred to, I hope you can answer them

1. What exactly is the difference between a skirted thermostat and a non skirted one?
2. Stupid question, does my 72 Imperial has a 440 3 engine? Don't know where the "3" stands for.
3. The Milodon thermostat you recommended is differently build than for example the Gates thermostat offered by RockAuto. Both can be used for my 72 Imperial 440 ci?

Patrick