Engine Runnin Hot Again

[55 Fargo]

Hi, just went to town to pick-up KFC for supper, went in the 47, about 7 miles each way.

The ambient temp is around 70, a beautiful day, but certainly not hot, and when driving the breeze is cool.

On the way into town the gauge was reading about 180, which is really about 165 as this gauge is out a bit, picked up the KFC and proceed home.

On the highway I was going about 55 mph, the engine was running nice, oil pressure 55 lbs, the temp gauge started to rise, it was about 205 on the last couple of miles, got home, and took a reading from the rad, I was still able to open the cap barehanded, the temp in the top of the rad was 195.

Now 195 on a 70 degree day with a cool breeze is way too hot, IMHO, what is up with engine.

This what I have done to date, replaced water pump 2 years ago, pulled freeze plugs, pulled dist tube, flushed block, had rad boiled out, it has very good flow, running a 160 t/stat, clean antifreeze about 50/50 mix.

Now what the "H" is going on here, what would happen on a real hot day, this symptom happens at high speed rather then low speed, but once hot stays hot.

The bottom rad hose does not collapse, the fan belt is snug.

Does anyone happen to know what might be causing this?

I have never taken apart my manifolds to see what position the heatriser plate is in, I don't think the heat riser plate would cause this engine to get this hot.

Engine timing seems fine, easy starting, runs nice.

I want to resolve this problem before hot weather, as what good will this be, I won't be able to go out for cruises on hot summer nights

A friend mine here keeps pointing his finger at my rad, this rad is a honeycomb, but is celan and has decent flow, I bought it from Tim Adams, it is a good rad. This friend figures it needs re-coring, I don't think that is the problem.

The engine keeps it's cool 160 to 175 at temps from 32 to 55, it gets hot under the collar from 65 and beyond, this has been my observation at least.

Sorry for such a long post, but need advice on this heated matter..............Thanx Fred

[Dodgeb4ya]

Your temperature guage could be miss leading you. You need to accurately check the engine temp. Use an infared temperature scan tool to check head/block and radiater temperatures accurately. You can pinpoint spot check temperatures on any point you want accurately. The tool will also pinpoint areas in the radiator that are not flowing properly. Run it W/O the thermostat and see what happens, it might not be opening.....

Bob

[Normspeed]

Fred, another thing could be a sticky thermostat. You can test them in a pot of hot water, with a kitchen thermometer to check the opening temp.

[40phil41]

Fred,

I know this isn't of any help but I had my '40 out today for the first time this season (remember it has a D24 engine - Cdn. long block). I let it warm up idling and the temp. steadied out at 160. Took it for several spins around the block at about 40 mph max. The temp. held at 160 when driving and when idling after I got it back home. The amb. temp. here is much like your place; 70 degrees with a cool light wind. A beautiful spring day.

P.S. The '40 runs real fine :-)

Phil

P.S. P.S. I did all of the things to my engine that you have done to yours but in my case the boiling out of the rad. was what cured my over-heating problems. Could your rad. need more time in the hot tank?? Just wondering.

[55 Fargo]

The geauge has been tested and is out a bit, but the thermometer I use in the top of the rad is dead on tested gainst other accurate thermometers.

So I do think the water is hot.

I would never run without a t/stat in this engine, I did this before and it was worse than now, not being critical ,But I believe in t/stats. the rad has a nice uniform temp difference from top to bottom.

I really think I have more crud, or something is still blcoked somewhere.........Fred

[55 Fargo]

Hi Norm, I have had this stat out before, tested it in hot water, it seems fine.

According to my Chrysler shop manual, the 160 t/stat should start opening at 157 to 161, and be fully open at 183 degrees.

Having said this, I would prefer my engine run in the 180 to 185 range, I really think 160 is too cool, but 200 and over is a bit scary.

[55 Fargo]

Phil, you got to take it out on the 401 and go 55 to 60 mph for several miles, then take a reading. Bet it would be a little higher than 160, unless that is your normal temp even on long drives in summer...........Fred

[Normspeed]

I'd say go for that infra red scanner gizmo. Any excuse to buy another tool.

Fred, if I remember right, the motor has never been dismantled and hot tanked? The scanner or remote thermometer gadget could help you determine if there's blockage in the water jacket that you haven't reached.

[Plymouthy Adams]

checka you timing

[Normspeed]

Good point. That could affect it for sure.

[40phil41]

Phil, you got to take it out on the 401 and go 55 to 60 mph for several miles, then take a reading. Bet it would be a little higher than 160, unless that is your normal temp even on long drives in summer...........Fred

Fred,

I am sure that you are correct. Last summer it ran at about 180 after the QEW trips in warmer weather.

[55 Fargo]

Now thats a good summer temp to run in these engines, 180 to 190, better than 160, which is too cool IMHO. I would be happy to run at 175 to 190 in hot summer weather, but on a day like today, it should be at 170 to 180, not 200..............Fred

[Rodney Bullock]

Fred, you are not going to like this:mad: however I have to say it. The thermostat is a 160, throw it out, get rid of it. You think it's helping you, it's not it's hurting you. You have got to go with a 180. As long as you keep that 160 you will always be chasing the temp. Please change it and you will cure half your problem. the other half has to do with your water/antifreeze mix. I know they tell you 50/50 and all that, you have to find the mix that works in your car. I want you to enjoy your car like enjoy mine. when I used the 160 thermostat I was always having problem..alway. what kind of cap are you running. if your cap has a spring in it...throw it away you are suppose to have a non pressure cap and that cap has to have a rubber seal under it so when the system builds pressure, if the cap is not letting the system build then the therostat is not going to open when it should.

[Dodgeb4ya]

The un-cooled coolant comes in at the top of the radiator- your warmest temp reading. Coolant is cooled as it travels down Radiator and into the water pump, then thru the distribution tube and block. It`s true that you should always run a thermostat as it promotes complete coolant flow to back of the block/head. If the block is clean and the radiator is absolutely flowing ok- then timing off/combustion gases leaking into coolant via leaking head gasket- super heating coolant/ faulty thermostat or wrong style- bypass housing, head gasket W /bypass hole wrong 1950-1951. Fan blade on backwards? Head milled too much-too fast of heat transfer/block bored too much-.080? Using Chinese gas?

Bob

[Young Ed]

Gotta disagree on the 160 being at fault. I have a 160 in both of my flatheads and they run 160 most of the time. Hotest part of the summer they do go up. But the way I see it is they would probably go beyond 180 too if I had that temp thermostat and being at 160 just gives me 20 degrees more capacity before boiling over.

[Guest rockabillybassman]

I think it just goes to prove that KFC is bad for ya!

[55 Fargo]

So what do you guys think, should I try and flush the block again, pull water tube again, or what.

I get the feeling, the coolant is being restricted somehow.

I did the exhaust gas leaking test before, no bubbles in the rad, I have even done it with the water pump without the fan belt and looking into the t/stat hole, no bubbles......Fred

[Don Coatney]

what kind of cap are you running. if your cap has a spring in it...throw it away you are suppose to have a non pressure cap and that cap has to have a rubber seal under it so when the system builds pressure, if the cap is not letting the system build then the therostat is not going to open when it should.

Rodney;

You are way off base here. The radiator cap has nothing to do with venting on a non pressurized system. There is a vent tube located at the very top of the radiator that will not allow any pressure to build in the system.

Also pressure has nothing to do with the thermostat opening. That is why it is called a thermostat not a pressurestat.

In the picture below I am pointing to the radiator vent. Also Rodney what year engine do you have in your car? Looking at the pictures I have of your engine I notice you have a internal by-pass system.

Fred;

I am with Tim on the timing issue. Your engine will run great with 5 degrees of timing advance. But it will also run hot. Back off the timing to 0-2 degrees and your engine will still run great but not so hot.

[55 Fargo]

Don, here is the dumb question, is advanced timing late timing, which can cause a hotter running engine, what is early timing, being retarded as I feel askiong this question.

I have turned the dizzy back clockwise slightly.........Fred

[Don Coatney]

Fred;

Advancing the timing fires the spark plugs before the piston reaches top dead center on the compression stroke. Theory being the fuel charge will take a split second to ignite and by the time it ignites the piston will be at or past top dead center. Advancing too far causes detonition or spark knock and this is not good. Do you have a timing light?

[55 Fargo]

Don, I never hear any spark knock on acceleration, but who knows. I have read that late timing or a vaccuum advance that is not working can cause overheating too. I knwo the vaccuum advance works, as I have seen it advance on acceleration, while timing the engine last year......Fred

[Don Coatney]

Don, I never hear any spark knock on acceleration, but who knows. I have read that late timing or a vaccuum advance that is not working can cause overheating too. I knwo the vaccuum advance works, as I have seen it advance on acceleration, while timing the engine last year......Fred

When I had my timing advanced too far I did not hear it until I was climbing a long steep hill. Then it sounded like a rod knocking

[55 Fargo]

Hi all, just got back from a test ride, ambient temp around 45 to 50, with a brisk wind.

Drove the same route as yesterday when she was overheating, about 10 to 14 miles, also drove the same speed about 55 mph.

Going with the wind, the temp went to about 160, going against the strong wind temp went to 165 to 170, on my last couple of miles, on my road, going 35 mph, temp was reading about 165.

So what is up, if the block were plugged up with gunk, would it not get hot even though it is cool this morning, is the rad suspect, or am I not figuring this one out.

This winter I idd take a ride on a very cold day around 0 to -4, I covered the rad with cardboard and a hole in the middle of the cardboard to allow some air to go through. On the highway, the temp soared to 200, like nothing, I removed the cardboard, and she dropped right back to 170 in a few minutes.

Maybe I will get the rad re-cored, maybe it is time for that, but I want to make sure all is okay before I shell out $350 for a rad job.........Fred sp could a heatriser stuck in the cold position cause overheating on warm days, I doubt it would do that I suppose

[Rodney Bullock]

I see, the vent tube on top of the radiator prevents pressure build up. I think you told me that before, I will make sure to remember that. Yes the thermostat opens according to heat not pressure, I should know that to. OK Don, anything else I need to relearn about my motor? O yeah, the internal by pass, mine doesen't have that little hose. I made a copy of your post so I can remember thanks.

Boy with all the things I got wrong it's a wonder my car runs at all:D Oh, my car is warming up outside, going to get more flowers this morning. Bye;)

[40phil41]

The engine keeps it's cool 160 to 175 at temps from 32 to 55, it gets hot under the collar from 65 and beyond, this has been my observation at least.

Fred,

After re-reading your original post, FWIW, I think that the guys suggesting re-checking your timing may be on the right track. You seem to heat-up at higher RPM's. When I had my over-heating issues they occured even at city driving speeds (30-40 mph) in the heat of summer.

Good Luck,

Phil