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Block heater questions

Z

Zoro

NAXJA Forum User
Location
Colorado
It was -5 this morning and the XJ sounded like it was going to die as I was starting it, the starter turned the motor over so slow I thought I had a dead battery so I'm looking into block heaters, I know you install the ones that heat the coolant on the lower radiator hose so what should the ID be of the lower radiator hose on a 90 XJ with a 4.0? About how many watts should I be looking for? I've seen them from 200-2000 watts. Also, is there any advantage to the ones that heat the oil over the ones that heat the AF and vice-versa?

Thanks
 
i beleive the ones that came stock went in the first or second freze plug. they have some out there that circulate your cooling water so the second you turn your car on you have heat but that seems like a little much to me haveing some motor and heater running all the time.
sorry i couldn't help ya on wattage but you may want to call your local jeep stealership and just see what they use.
 
bj-666 said:
i beleive the ones that came stock went in the first or second freze plug.
Click to expand...
Thats what is in my 95(dont need it here)!
 
You might double check your battery and connections, my jeep has always started even at -20. If youre consistently cold where you live then try going to a 5w30 or even a synthetic.
 
I installed one on my '99, went right into the first freeze plug (on the side of the block, under the manifolds...it plugs access to a coolant jacket in the block). I've never had trouble with any of my XJ's starting in cold down to -15 here or in NY/NJ. And $35 is cheap insurance against one morepossible hiccup. That's how I look at it. I think the heater I installed is 1200 watts. Keep in mind that you need an outlet that will support that kind of draw. A 2000 watt heater draws about 18 amps at 110 volts (more than most house outlets). We have block heaters on most of our trucks at work and it's a little tricky finding homes for all the trucks so that breakers don't pop when we plug them in. On a cold night, I wouldn't imagine anything less than 7-800 watts would do a whole lot of good. The in-block heaters make a lot more sense to me than in-line. You're heating up the coolant in the block first, then the heat bleeds out to the radiator. Any coolant that is still cold gets a little warmth when it hits the pre-heated jackets in the block. That's just my opinion. And I have been called a lot of names. :wierd:

-Rich
 
I just ordered 2 in-line type heaters for both of mine from NAPA. When compared to the freeze plug heater, the in-line appeared to be easier to install and, while they may not work as good as the freeze plug type, they will work better than nothing. They costed 35 bones a piece. I haven't installed them yet and it's warmed up a bit now so I can't give any reports. I believe they were 630 watts.
 
For the lower radiator hose type do you have to cut the hose or does it install on the water pump or radiator side of it?
 
If you use the one that goes in the heater hose, follow the directions well. I put one in a medium duty older deseil truck once. It is my understanding they work by self-circulation, for lack of a better terminology. As the water heats, it rises and is replaced by the cold water comming from the bottom of the block. So, if I remember, it has to be lower than the top of the block, so the warmed water can rise, and depending on what year you have, the heater bypass valve should be open for early models, or I think it can still circulate in late models regardless.

Am I correct on this anyone?
 
riverfever said:
I just ordered 2 in-line type heaters for both of mine from NAPA. When compared to the freeze plug heater, the in-line appeared to be easier to install and, while they may not work as good as the freeze plug type, they will work better than nothing. They costed 35 bones a piece. I haven't installed them yet and it's warmed up a bit now so I can't give any reports. I believe they were 630 watts.
Click to expand...


EXTREME CAUTION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

These type of heaters are known to overheat or malfunction and cause minor to MAJOR damage, including underhood fire.
The block heaters are factory, reliable and fairly easy to install.
 
How about just a battery heater?

less wattage, no messing with the engine-

on mine it seems to be the battery that causes the slow starts in the morning.

just a thought.


B
 
Last year I bought one of the factory freeze plug block heaters, It was a breeze to install, took about 5 minutes.

All you have to do is pop out one of the freeze plugs (round brass cups in the side of the block) from under the manifold, and put this little heating element in, and tighten the nut that seals it in the hole with an O ring.

It works Pissah...when its below 10 degrees I have heat first thing in the morning.

It only costs about 30 bucks from mopar, and it comes with picture directions.
thats your best bet
 
creeperjeep said:
Last year I bought one of the factory freeze plug block heaters, It was a breeze to install, took about 5 minutes.

All you have to do is pop out one of the freeze plugs (round brass cups in the side of the block) from under the manifold, and put this little heating element in, and tighten the nut that seals it in the hole with an O ring.

It works Pissah...when its below 10 degrees I have heat first thing in the morning.

It only costs about 30 bucks from mopar, and it comes with picture directions.
thats your best bet
Click to expand...


what all do you have to remove to get at that freeze plug? you're talking about the ones below the manifolds?- can you get at it from the bottom or the side, or do you have to remove the manifolds?


B
 
BCParker said:
How about just a battery heater?
less wattage, no messing with the engine-
on mine it seems to be the battery that causes the slow starts in the morning.
just a thought.
B
Click to expand...

Forgot about the battery heaters, good call.
 
I'm pretty sure it's not the battery or the connections themselves as everyone I know with a 4.0 in a Jeep has sluggish starts when it's cold, mine always starts it's just that when cold the starter itself sounds slow. I'm running 5w-30 semi synthetic.

For the freeze plug types, do you have to drain any coolant?
 
Zoro said:
Question, are freeze plugs the same size on most engines or are they different sizes diameter and thread wise?
Click to expand...
They aren't threaded. They are press fits.

It is not necessary to remove the manifolds to install the factory heater on an XJ -- at least, I can attest to that for an '88 4.0L. Drain down the coolant, take a punch of some kind and drive it into the first freeze plug on the drivers side, and twist to remove the plug. Follow the directions to install the heater.

It's done from underneath.
 
XJ4PLAY said:
EXTREME CAUTION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

These type of heaters are known to overheat or malfunction and cause minor to MAJOR damage, including underhood fire.
The block heaters are factory, reliable and fairly easy to install.
Click to expand...

If they're both electrical units from NAPA, what would make the in-line one more prone to malfunction than the block freeze plug type?
 
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