You speak of VERY little experience. Yes you work on your precious old car, I work in the field and have most likely more years than you are alive. The fact is if you are out of coolant you just lost heat transfer. The combustion chambers over heat while the rest of the block slowly absorbe the heat by contact. Until the heat transfers to the rest of the engine the coolant gauge will most certainly read normal if not cold. The red light will act the same way. If the cooling system is low the light or gauge will read normal to hot back to normal as the air pockets come and go. It is a fact. Many customers continue to drive after they see lots of vapors escape from under the hood and notice the coolant gauge drops. They think it's ok till the car just stops. The engine is now destroyed.
Nice theory, but the steam in the system from whatever amount of coolant is remaining in the block is enough to heat the sensor enough to read hot. I've seen this on small block Fords and also heard the same from others. That is to say people who have observed a car with the radiator drained trip the overheat light.
In my experience a small block Ford (an engine, not a "precious old car", which has been in production well into the '90s). Furthermore, I'd hardly call en engine which has been run until overheated destroyed. Common failures in an engine subjected to such conditions are head gasket damage, ring damage, and possibly bearing damage also on aluminum headed engines the heads will sometimes warp. All of these are fairly cheap fixes and the engine is by no means "destroyed". A simple hone, re-ring and new bearings and possible milling of the heads is usually enough to get the engine running well again.
You keep on believing whatever you like, but I sure as heck would never let you touch any of my cars with a 10 foot pole. Your ineptitude is glaringly obvious.
With an good used engine running between $500 ~$2000 for most cars and with shop rates running between $50 & $100 Per hour your "cheap fixes can quickly eclipse the market value of the vehicle. Even if the engine rebuild/ "cheaply fixed" is done any reputable mechanic will have to install new belts hoses & fix whatever caused the overheat. Add to that the cost of a rental vehicle what the engine is being "cheaply fixed" and you're starting to talk money.
A simple "milling of the heads, hone, re-ring, new bearings, magna flux, etc, etc, etc." costs money in the world that I live in. Perhaps it's cheaper on the planet that you reside.
How so? Fact is if there is no liquid in the system, no steam. When a hose blows the liquid is pumped out by the pump the rest is boiled off. No theory, basic science.
Once the area that the sender is screwed into gets hot enough yes. With out coolant, there is a lag. Coolant which is liquid is the heat transfer medium. If the red light comes on or the coolant temp gauge shows hot with out liquid in the system, the engine is now damaged enough to be beyond cost effective to repair, replacement is the cost effective route.
Run with out coolant is destroyed. How many have you taken apart after 10 miles of no coolant at 70 MPH? Even an engine with low coolant will suffer enough damage to be replaced not repaired. The cost of parts, machining and labor would put the repair easily over the cost of a re-man engine.
Cracked heads. broken pistons and rings that damage bores, stuck valves that impact the pistons causing piston damage and head damage. That only names a few very high overheat damage.
Only to be back in the shop a short time later, you just gave the customer a free engine. Do that enough times you are out of business. Now you also have the problem of a bad rep which has the highest price value because you have no idea how many customers you lost because on that one upset customer.
Keep reading "popular hot rodding" and other rag's of the like. You will remain as ignorant as you are well into the future. Others in the past has told you in posts that you are very ignorant, I'm doing the same.
Personally if I am on a tight budget I will just do the minimal amount of work it takes to get the motor running properly again. That may mean not doing a full rebuild (which may not be necessary anyway), or even fully disassembling everything, let alone magnafluxing the block and/or heads (which really wouldn't be necessary unless overboring by a large amount).
Rings - $25 Main bearings - $23 Rod bearings - $23 Head gaskets - $28 Intake manifold gasket - $8 Oil pan gasket - $9 Incidentals/misc - $25
-Total: $141
So for under $150 a cheap 'rebuild' can be done. I quoted those prices from Advance and they are for a small block Ford. If you are on a tight budget you may not even need to replace all or even any of the bearings in an engine that has been overheated. Perhaps the rings survived, whihc is not unreasonable.
The rings were fine on the 289 which I ran without collant for 500 miles, most of those miles were WOT on the highway doing 75-85 MPH. When I sold the car 7 cylinders read 100 PSI on the dot, and the one that read low (~60 PSI) was low due to a burnt exhaust valve. That valve was burnt when I put the heads on the car. I needed a car right away so I put to gether what I had and other than being low on power form the open chamber ehads it ran quite well.
In any case, $150 for a cheapie 'rebuild'. If the heads are warped/not flat they can be resurfaced for $100 or less. $250 for a freshening up that should last a good while is not bad in my opinion. I mean honestly, compared to the potentially several thousand dollar shop work you propose it doesn't seem bad at all. Heck, if you don't wanna spend the money to have the heads resurfaced at a machine shop you can do it yourself with a belt sander (works wonders on exhaust manifols, and will do just fine on heads). These things can be done for cheap. The book value of my car is much more than $250.
This stuff may seem a bit overwhelming, but honestly anyone with a little patience and desire to learn can buy a book and rebuild an engine. Sure the average Joe probably couldn't do all this in a weekend if it was his first time, but the point is that an engine which has been overheated is far from destroyed. Something that might destroy an engine is throwing a rod. When that rod breaks loose it can take a lot of things out before it puts a hole in the oil pan. With a destroyed crank, at least one head, possibly block, possibly other parts of the rotating assembly (depending on how it broke, what it hit on the way out, what RPM it let go at, and how quickly the motor was shut off) that is when one may consider an engien destroyed, instead of just broken or in need of repair. In any case, $250 sure beats $2000-$4000 for a new engine.
So now you're changing the situation. Originally we were talking about my '67 289 which I ran for 500 miles at WOT on the highway with only the small amount of coolant left in the block after draining the radiator and pulling the heads. No leaks in thes ystem, just a very small amount of coolant.
I've never argued that point. I thought that was obvious that with only steam in the system vs a liquid there would be a delay to the temp sensor.
Not necessarily. $250 for a budget 'rebuild' (rings, bearings, resurface heads) could very well do the trick (which is certainly cheaper than $2000-$4000 for a enw engine). In the case of my 289 the rings and bearings were just fine. I had 100 PSI on the dot across 7 cylinders, the one that read 60 PSI was low due to a burnt exhaust valve which was a problem when I put those heads on the motor. The bottom end at that time had over 200,000 miles on it and the original heads only failed when revving the motor to 7 grand one time too many for heads with 200,000 miles and worn valve tips, resulting in a snapped rocker stud.
My 289 (200,000 miles on that engine) was run with virtually no coolant for
500 miles at WOT, doing 75-85 MPH. That's 6 hours of run time. I never tore into the bottom end, but as I stated it did make 100 PSI on the dot on 7 cylinders and the only reason #5 read 60 PSI is because of a burnt exhaust valve which was present when I swapped the heads. Those 500 miles with hardly any coolant were right after swapping the heads.
Possible, but unlikely. Most engines I've seen that have overheated run just fine. Obviously my 289 was an exception to the rule. I believe most motors would have seized up under such conditions.
I'm not running a shop. I'm talking about an individual fixing his own car. If I were running a shop I would recommend a complete disassembly and rebuild if going so far as to do a re-ring and replace the bearings. When paying someone else to do the work the additional cost of machine work and such is relatively small when compared to what one is paying for the 'budget rebuild'.
I don't read such magazines. I speak from experience. Also, I could take plenty of potshots at you based on what opinions others have expressed about you, but I won't. There's not much point in that. I'm debating/arguing an issue here, not bashing you.
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