Getting the motor hot faster.

[MARTINSR]

I am driving a stone stock 1995 Ford SHO Taurus learning a lot from this site, I'll tell you that. Anyway, on my way to work today I was thinking about putting some rad cover to heat the thing up faster being I looked at the temp guage a half way to work and it was still cold!

Then something hit me, what the heck is a rad cover going to do when theoretically the water in the motor isn't even going thru it until the thermostat opens!

How can you get the motor to heat up faster?

Brian

[RandomFact314]

1) Grill block is always one of the easiest things to do...

2) Sometime you can find thermostats that open at a hotter temp that you could replace yours with...

3) If you want to spend money, I heard a block heater helps a ton... You hook it up like an hour before you start driving and it pre-heats the engine block for you...

[JohnNeiferd]

A grill block will help slightly because even if the coolant isn't flowing through the radiator, it is still transfering heat out through the engine block itself at a much slower pace. By blocking the grill you also slightly reduce the amount of air passing over the engine itself, this will help even if it is only very slightly.

Using a hot air intake will help as well as the engine will be sucking in warmer air with each revolution instead of colder air that contributes to cooling as well.

[Christ]

Ok, here's the thing -

People always think that the thermostat doesn't open up until the engine is already up to temp. While this is partially true, it's also partially false.

On a full warm-up cycle, depending on conditions, the thermostat could open 5 times... It could open 10 times... Hell, it could open 35 times.

What actually happens in your coolant system is that the local (near the thermostat) coolant heats up. This causes the stat to open, allowing the water pump to push the coolant through the stat, into the radiator, where it is cooled.

Ok, so the coolant gets cooled by the radiator, right? Right. What happens to the already cold coolant that was in the radiator when the hot coolant displaced it? Oh... it goes back into the engine. Cold coolant hits the thermostat, and it closes, right? So now the engine has to heat the coolant back up to temp, open the thermostat, and allow the pump to push it out into the radiator... So that coolant leaves, and some of the already warmed coolant goes back into the engine... so the stat stays open? Nope.

Remember, the first set of coolant was in the radiator. What does the radiator do again? It cools - that's right. So now, the coolant that was already heated once has just cooled down (here's the good part) a lot. Which means the engine has to heat it back up, to open the stat, to allow it into the radiator, to be cooled, so the already cooled coolant can flow back into the engine, to be heated back up, so on, so forth.

So, you can see that a grille block will help warm-up times in this manner. It will prevent the radiator from cooling the heated coolant so much/so quickly, meaning less heat energy has to be wasted back into it each time there is a thermostat cycle.

[Daox]

You think this happens even with the water pump cycling the water in the block? I would think it would be enough flow to eliminate hot spots... thats its job after all. Perhaps at low rpms... I can't say for certainty.

[Christ]

Originally Posted by Daox

You think this happens even with the water pump cycling the water in the block? I would think it would be enough flow to eliminate hot spots... thats its job after all. Perhaps at low rpms... I can't say for certainty.

No, I don't mean that there are hot spots, I was just explaining the cooling cycle that happens in the engine.

The water pump is constantly moving coolant, even if the stat is closed, so there aren't hot spots in the engine block. When the stat opens, it creates a new circuit which was previously cooler than the coolant in the block, which is then re-heated by the waste heat of the engine block.

I over-simplified it because it's a fairly difficult concept to comprehend at times. There isn't two specific sets of coolant at all times, since the coolant is turbulent, it is constantly mixing. What happens, though, is that the coolant heats up because of the block heat, and that opens the stat, which allows the coolant into the radiator, where it cools. The previously cooled coolant enters the block, and when it touches the stat, the stat closes down to prevent the coolant from flowing into the radiator to be cooled again.

If you boil-test a stat, you'll see that at a specific temperature, it will *pop* open semi-violently. As you lower that temperature, it will slowly close back down. If you quickly douse it in colder water, it will snap shut with the same force.

The stat's job is to modulate flow at all times, so it doesn't just open and stay that way when the engine warms up.

Also, under dynamic operation, an engine will heat and cool consistent with load (lagged response, obviously), which means that the coolant will be more or less heated by the engine, accordingly. This means that the thermostat needs to be somewhat dynamic in it's ability to restrict coolant flow in order to keep the engine cooled (or heated) properly.

Hopefully, that made it more clear, instead of making it more obscure.

[comptiger5000]

I don't think it presents much of an issue, as the coolant in the block is circulating. By the time the thermostat starts cycling like that, the engine is up to temp, and the t-stat is keeping it there. On my Jeep, the upper rad hose stays stone cold until the coolant temp on the gauge hits about 180*, then the t-stat starts to open a little.

[Christ]

If it only opens a little, it's in need of replacement. It should reach temperature, then open fully.

The thermostat cycles open and closed from the time the engine first reaches temperature, which is long before it is actually warmed up. That's why it's called the warm-up cycle.

Following the OE temp gauge on most vehicles doesn't get you very far, they're somewhat muted because the average user doesn't like to see variations in the temperature of their engine. Fact is, your engine is almost never "rock steady" in terms of temperature. Temps are dynamic by the nature of engine operation.

I'll have more time later, if this isn't entirely helpful, but I've got to go, I have some money to make.

[MARTINSR]

Originally Posted by Daox

You think this happens even with the water pump cycling the water in the block? I would think it would be enough flow to eliminate hot spots... thats its job after all. Perhaps at low rpms... I can't say for certainty.

I don't think the water "cycles" in the block at all. I think Christ is right on the money. Think about it, the heater doesn't do crap until the thermostat opens, because the cold water is just trapped in there. The water pump is "sucking" coolant in from the bottom of the radiator. That water would have to have a place to go, if the thermostat is closed it doesn't, so the pump is just spinning it's proverbial wheels.

I don't think there is much power behind the water pumps design. I have always wondered this, and I have always assumed that the pump sort of "moves" water around but not with a whole lot of force.

I can certainly see that if the water gets hot enough right at the thermostat as Christ says and it opens allow some hot water thru then the pumps push is enough to let some of that cold water sneak past the thermostat. But it makes total sense that the thermostat MAY (not completely convinced that it will do as Christ suggests) but it makes a heck of a lot of sense.

Brian

[MARTINSR]

Sorry my last post was writen while Christ was already answering it.

Brian