Runaway heat, hard starting, rough idle and etc

Engine, fuel system, cooling system, heating, carburetors, exhaust, transmission, wheels, and other items related to the moving the car.

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Wixomhead
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Re: Runaway heat, hard starting, rough idle and etc

Post by Wixomhead »

Update:

I have not yet tackled drain plug/flush. Still on the radiator and now water pump rabbit hole.

TDC is accurate: #1 at top of stroke 10 deg before (rising) and 10 deg after (falling) by the feel of the socket extension I'm holding in the plug hole, against the top of the piston.

Autolite 4300 rebuild kit came yesterday - accel pump "dribble" (hard start/stumbling) to be completed - once heat issue solved.

Yes, the car was running a 'bit warm' last year into this; only AFTER I R&R'd heads AND drove 500 miles did it seriously start overheating (see orig pic up top).

1. Radiator came back from one of the last true radiator shops w/in 50 miles -$45 flush/inspect and he says it's in "great shape" (so I saved $500+. Why am I so disappointed :)

2. I handed him my clutch fan for fun. There was gunk all over the front/bi-metal coil, but he said DON'T TOUCH IT. He didn't see it as source of problem - when hot, it won't free spin more than 1/4 turn and it's definitely pulling air. Also - heat is happening idle OR highway, no diff. Sugg running w/ no thermostat which I get - but I've been through three thermos, one of them a high flow ...

3. He suspected water pump - if orig design - vanes likely corroded down to nothing. I pulled that this morning, and it's obviously a replacement / in excellent shape so far as I can see (pics). No bearing noise, no leaks, no wiggle. Again - oil shows ZERO signs of contamination. Leftover coolant is very green...

4. I shot garden hose jet into water pump inlets on block. Lots of green, light green, lots of white foam and clean water coming back out of other water pump port as well as top of intake manifold / thermo housing etc.

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Wixomhead
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Re: Runaway heat, hard starting, rough idle and etc

Post by Wixomhead »

Reassembled, without the thermostat.

Drove for :30 today, gauge crept past halfway but during 30-40 mph cruise and idle mostly stayed below halfway. Car still hesitates/stumbles at tip in, much less noticeable when hot but terrible when cold. Choke is adjusted properly (?) mostly closed when cold, fully open when hot. I sprayed starting fluid all around carb base but no changes.

Filled rad (temporarily) with 100% straight tap water. Car was on slight incline so front higher than back; filled rad to within a couple inches below neck. Ran engine cold and boy that water is really flowing well out of the tubes.

Reduced idle as low as it would run with smoothest idle - it's LOW ... t car will creep (not jump) fwd in gear. Idle mix screws cannot be turned more than 2.5 turns in else engine stumbles.

Infrared thermometer arrived - after 40 mins of driving, let it idle and took some temps. Cool gadget, hope it's accurate ($28 Amazon special).

New radiator inlet hose: 180 deg
New outlet hose: 180 deg
Themo housing: 206
Rad tank (just below inlet nipple): 206
Rad tank (just above outlet nipple): 201
Top of rad cap: 132
Just below cap: 170

Vacuum hose at rear of carb (to PCV valve in pass valve cover) is just about pinching itself closed - really strong vacuum there.

Oil is as clean as new.
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TonyC
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Re: Runaway heat, hard starting, rough idle and etc

Post by TonyC »

Hmpf... :think: honestly, I don't have input this time for the symptoms. Maybe attaching a vacuum gauge to the engine could give an idea. Have you tried that? Depending on how the gauge reacts, you could get an idea where to focus your search for the gremlin's hiding place.

On a side note, I noticed the pictures, which seemed to give visual testament to Ron Baker's caveat regarding 460s. I saw some serious corrosion on the timing cover right at the water pump area. I saw a lot of oil sludge on the back of the steel plate. That tells me Ron was right about the casting flaw, that the timing cover has a hole or several holes in it right at that area that's supposed to be the weak spot; and the plate was doing its intended purpose, making sure that leaking oil had nowhere to go and keeping coolant from spilling into the crankcase. That's a good thing. At least we know the engine problems are not related to an oil/coolant mix. That is why Ron Baker gave that warning, and why I reiterate that warning to 460 owners here.

---Tony
"Don't believe everything you read on the Internet, just because there is a picture with a quote next to it." (Abraham Lincoln, 1866)
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Re: Runaway heat, hard starting, rough idle and etc

Post by action »

Some of your temp number don't make sense.
The two that are relevant are ..
The temp at the T-stat housing at 206. Would like to see a higher number in the 210 to 220 range and you have no T-stat
The temp going back into the engine from the radiator outlet is 180.
So there is a 26 degree drop after the coolant passes through the radiator.

I assume your statement below you drove for 30 minutes. If true, I would say install a thermostat and coolant, bleed any air out and the cooling system is good. Which addresses the runaway heat issue.

BTW the job of the thermostat is to get the coolant up to temperature as fast as possible. Depending on the rating that is 180 to 195. At that point the thermostat starts to open. (Actually there is a bleed and a by-pass where coolant still moves) Usually fully open in 5 to 10 more degrees. Once that temp is reached the thermostat is fully open and passing coolant. In the world called perfect the coolant temp out of the engine will be over 210. With a good pressure cap and correct coolant mix the boiling point (over heating) is in the 240 to 260 range.

BTW The gauge in the instrument cluster is not that accurate.

Your drivability issue - If the engine hesitates and stumbles on acceleration more noticeable cold, the areas to look at are
Accelerator pump stroke setting
Accelerator pump check ball
Or accelerator pump
Choke setting
Air cleaner heat door operation
Vacuum controls for other engine functions (Leaks in vacuum lines or vacuum functions)
Float level

Action
Phoenix - Yeah, it's hot, however it's a dry heat
2006 Lincoln Navigator Limited 5.4l 3V
1996 Lincoln Mark VIII 2DR Coupe Diamond Anniversary 4.6l DOHC, 4R70W, 3.07
1970 Continental Mark III Triple Black 460 4v, C6, 2.80 (Used for Woodward Dream Cruise or just generally stored in Michigan)
1966 Lincoln Continental 4DR Convertible 462 4v, C6, 3.00
1966 Mercury Park Lane 4DR Breezeway 410 4v, C6, 2.80
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Re: Runaway heat, hard starting, rough idle and etc

Post by Wixomhead »

So...hoping I can bring this thread to a close.

* Looking again at the shop manual - I bent the accel pump linkage and moved the pin so as to draw as quick & healthy a squirt as possible out of both nozzles. Huge difference, much better throttle response off idle.
* I adjusted idle, timing and idle mix screws one last time - ended up at closer to 12 degrees BTDC (no detonation that I could detect), at least 2.5 turns out, 17.5 inches vacuum, very steady, but not 100% steady...100K motor, who knows.
* Drove 30-45 MPH for an hour around town, let it idle for 10, too. Factory gauge took 20 mins to reach halfway, but once there, arbitrarily swept barely just below and barely just above halfway point. Even with AC on, slow traffic, did not see it get any higher.
* After an hour of driving, popped hood, at idle, infrared shows 205ish thermostat housing, 200 at rad inlet tank - and outlet tank. Can't seem to identify any temp change across radiator, maybe I need to get more precise with instruments/probes.
* Will drain cooling sys and fill 50/50 and assume all is well.

Thanks for all the input and help and hope this thread helps others...
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Re: Runaway heat, hard starting, rough idle and etc

Post by TonyC »

Well, good, here's hoping your issues are in fact resolved. When you put in the proper antifreeze/water mix, remember to factor in the water that's already inside the block when you're estimating that 50/50 ratio. That water will not go anywhere when you drain the system, unless you remove the drain plugs at the block as well. If they're easy to access, I recommend doing that to ensure a total drain. If they aren't, then remember to factor in at least one gallon of pure antifreeze in the stock you intend to put in, so that way you can rest assured that you have the minimum 50/50 mixture; otherwise, you could end up with below that ratio.

---Tony
Last edited by TonyC on Wed Aug 04, 2021 5:08 pm, edited 1 time in total.
"Don't believe everything you read on the Internet, just because there is a picture with a quote next to it." (Abraham Lincoln, 1866)
"Question Authority!"

1966 Continental Sedan, affectionately known as "Frankenstein" until body restoration is done (to be renamed "General Sherman" on that event)
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Re: Runaway heat, hard starting, rough idle and etc

Post by action »

Put a thermostat in as well.
Both your wallet and the engine will thank you.
On a cold start you want the engine to heat up as fast as possible.
After the thermostat replacement there may be air in the system that has to work it's way out. That will occur over the next several trips. Check fluid leves and add as needed

Action
Phoenix - Yeah, it's hot, however it's a dry heat
2006 Lincoln Navigator Limited 5.4l 3V
1996 Lincoln Mark VIII 2DR Coupe Diamond Anniversary 4.6l DOHC, 4R70W, 3.07
1970 Continental Mark III Triple Black 460 4v, C6, 2.80 (Used for Woodward Dream Cruise or just generally stored in Michigan)
1966 Lincoln Continental 4DR Convertible 462 4v, C6, 3.00
1966 Mercury Park Lane 4DR Breezeway 410 4v, C6, 2.80
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Re: Runaway heat, hard starting, rough idle and etc

Post by LithiumCobalt »

Removal of the thermostat does not make an engine run cooler. Common misconception. As stated, the function of the thermostat is to warm the engine to a MINIMUM temperature.
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Re: Runaway heat, hard starting, rough idle and etc

Post by Wixomhead »

Argh.

Drained the petcock of water.

Poured 1 gallon straight coolant in - THAT filled the rad to 2” from top...hmm, that would mean 12 qts/3 gallons water remainining in the block?? Huh?

Reinstalled 180 deg motorad brand thermostat (checked operation in boiling water - opened and closed fine)

Drove 1 hour on the highway (over cape cod bridge, for those that know it) at 65 mph then 15 mins back roads. 75 degrees out. Temp gauge barely moved to above half. Happy. Went to Hagerty sponsored car show- great time, great cars, I was the only Lincoln ;)

NO LEAKS, no puddles, no surprises.

2 hours later, left for home. 85 degrees out. 20 mins in stop and go, gauge went again to just past half in traffic....got on highway and gauge soon crept up to closer to 2/3rds - ref the “P” in my orig pic. ALARMING.

Imm got of highway. Took secondary roads an hour more to home. Gauge moved a little bit lower than 2/3 “P”. A/C on or off didn’t seem to make any difference.

Pulled in the driveway. Put temp gun on thermo housing - read 220 deg. Later that day checked coolant level - 2” from top.

Noted a few ounces motor oil puddled in valleys, on top of timing cover. (?). Had to have come out of dipstick tube - didn’t see any leaks around distributor....... Oil level right at full mark on stick - as it’s been since last change.

Stumped.
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Re: Runaway heat, hard starting, rough idle and etc

Post by action »

At speeds greater than 40 to 45 mph it is all about the radiator.
The water pump and radiator fan are not much of a factor in cooling. The air blowing through the radiator pulls all of the heat out.

Now with that said, 220 f with a pressure cap and 50/50 coolant mix is a good number.
No coolant came out of the system, the definition of over heating. So you are good.
With the temp readings not changing with or without the AC on is a good indication the system is working well. The added load of the AC did not make a change in the gauge reading. Because the added heat was shed by the radiator.

The gauge was never that accurate. If the needle stays inside the bracket area on either side of TEMP you should be good.

Action
Phoenix - Yeah, it's hot, however it's a dry heat
2006 Lincoln Navigator Limited 5.4l 3V
1996 Lincoln Mark VIII 2DR Coupe Diamond Anniversary 4.6l DOHC, 4R70W, 3.07
1970 Continental Mark III Triple Black 460 4v, C6, 2.80 (Used for Woodward Dream Cruise or just generally stored in Michigan)
1966 Lincoln Continental 4DR Convertible 462 4v, C6, 3.00
1966 Mercury Park Lane 4DR Breezeway 410 4v, C6, 2.80
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