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Where does your temp gauge sit usually?

cheekychimp

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I know the stock gauge is a very poor method of measuring coolant temps but I still find it good enough to be able to warn me in good time if there is anything wrong.

I recently had two lower radiator hoses blow. Not blow off, they simply exploded leaving a two inch tear and dumping 80% of the coolant on the ground. When we replaced the hose for the second time we noticed the lower hose and lower half of the radiator was still only warm, long after the upper hose and radiator had reached operating temperature (and were too hot to touch). We dug into it a bit more and found that the radiator was seriously clogged. I replaced it and all seems fine for the moment but I noticed my temps are slightly higher than before.

Previously I'd be pegged at about 40% on the stock gauge, now at idle it sits closer to half way. I'm just wondering if 50% is normal and the temperature sensor in the bottom of the radiator wasn't seeing the correct temperature previously, or alternatively if I still have an issue. It's still relatively cool over here at present so I'd like to make sure everything is working properly before the summer gets here.
 

turbohf

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think mine is likes to hang out at around the same 40%... but i installed a real mechanical temp gauge a couple years back to keep a real eye on temps. stock gauges doesnt move past middle till beyond 230*F... and my car loves to drop temp down to 175* or so on a nice decel and/or cold weather cruising on freeway. factory gauge will show 25-30% or so.

i dont trust the stock gauges at all. not just the Galant also, noticed the same in several of my Honda's while logging items.
 

turbowop

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My stock gauge sits a little left of center.

I wouldn't worry about the lower hose and lower radiator tank being warm or cool. That means it's working. /ubbthreads/images/graemlins/smile.gif
 

prove_it

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Cheeky, the sensor in the radiator is for the fans, you asked about it in your first post. That doesn't have anything to do with the gauge. Not sure why it would read hotter now than before, but about 50% is where mine sits.
 

iceman69510

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Mine too. And agree with prove it on the radiator sensor not contributing.

Sometimes with low coolant flow and overheating starting in the head area, you can actually get lower gauge readings as the water may locally boil and the sensor may not read properly because it is not in contact with the fluid.
 

prove_it

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Possible. However, when that happens, generally you'll see higher readings due to the "steam" pockets that develop.

If it were up to me, I would get a new sensor anyway. They are cheap and easy to replace. If it's original then it's got 20+yrs of daily heat cycling.
 

cheekychimp

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So where is the actual temp sensor located?

Mark how cool is the lower hose and radiator on your car then? Cool enough to touch?
 

fuel

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ECU coolant temp sensor and gauge temp sensor are mounted on the under side of the thermostat housing, and then there's the sensor at the top which turns on the A/C fan if the car is overheating.
 

turbowop

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</font><blockquote><font class="small">Quoting cheekychimp:</font><hr />


Mark how cool is the lower hose and radiator on your car then? Cool enough to touch?

<hr /></blockquote><font class="post">

I honestly can't remember. It's been awhile since I grabbed the lower hose. But the lower switch kicks the fan on when the coolant temps down there reach 175°F. Which seems too hot to touch, but I could swear I remember grabbing the lower hose and it just being warm.
 

FlyingEagle

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Depending on the direct of flow, you generally end up with two hoses that are very close in temperature to the naked hand at touch.

One hose should be slightly colder, but you would normally have to use a laser temp gun to prove this or individual sensors inline with the hoses for feedback.

I change out coolant in cars daily.

I would drain the rad/hose and close it up, vacuum the system with a kit, then pull in new fluid with the vacuum valve opened to the a fresh container of 50/50.

I place a spill free funnel on the top and run the engine at midrange RPM to get heat and flow going.

I can tell you that some system take time to get up to temp on the outside portion/house past the thermostat.

You have to wait for the thermostat to open to get more heat in the hose attached to the thermo housing.

Once you have the thermostat opening routinely (higher ambient temps, towing, etc), your hoses are very much hot and will stay that way.

Trucks take the longest to get up to temp due to their capacity and design for towing and the related BTU's/energuy that must transfer/enter/exit the system.

I can't comment where my gauge sits because it's now relagated to behind-the-pod status.

Stock cluster used to read just past the hash mark, going to the right.

Different Mitsu car, but same cluster technology.


Paul, what coolant mix are you running in your car?

I have yet to see a 50/50 Ethylene glycol mix with water, do what has happened to your radiator, assuming the mix is kept up to par in terms of age and purity.
 
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prove_it

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If your lower hose is as hot as the upper then your radiator is junk, or your fans are dead or highly insufficient. Coolant flows in the top and out the bottom. You should see a t least a 30-50 degree difference. It's noticeable. Upper will feel like a burn on your hand as it's at 200* or higher. The lower should never exceed 180*. This is of course at full operating temp.
 

misterfixit

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Check your thermostat is working.

Pull it off the car and inspect it. It could be failing. They typically fail stuck partailly open.
In which case the car will warm up slowly then fail to dump excess heat (restricted flow)

Easy to check in a pan of water on the stove.

It should be fully closed. then at the opening temp happily go to fully open. then in cold water it should fully close.

Rich
 

cheekychimp

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Rich, I will check the thermostat but everything appears to be okay now other than the gauge pegging slightly higher than previously when at idle (temps drop nicely on the highway with airflow through the bumper and grille).

I am using a 50/50 mix, I think the junk in the radiator got flushed out of the engine. Obviously someone ran straight water at some time and let it sit. The daily has never been off the road for any length of time since I've owned it. I'm running the stock AC fan with the stock condenser and then a 5 blade fan on the radiator which is as big as the OEM unit. It's no world class motorsport setup but I really don't think the fans are an issue, they kick in fine, move plenty of air and keep the temperature stable. I don't have a temperature gun so I can't check the exact temps of the two hoses but both are too hot for me to touch (maybe I'm just a ***** Brit). The problem before was that it was possible to grab the bottom hose and lower radiator long after the car had warmed up and the top hose and upper radiator were far too hot to touch. Water just wasn't circulating but the water pump is brand new. It might be prudent to check the pump again though given all the crap that was in the radiator.

Temperatures seem to be stable now. I guess I should get round to doing another of the dash pod retrofits and install a water temp gauge so I know exactly what the temp the coolant is.
 
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prove_it

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Sounds like a internally plugged radiator to me too. How old is it?
 

cheekychimp

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No idea, I got it second hand and it appeared to be in good shape. Who knows, maybe it was dirty inside from day one /ubbthreads/images/graemlins/dunno.gif

The replacement is new at least!
 

cheekychimp

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Quoting iceman69510:
Mine too. And agree with prove it on the radiator sensor not contributing.

Sometimes with low coolant flow and overheating starting in the head area, you can actually get lower gauge readings as the water may locally boil and the sensor may not read properly because it is not in contact with the fluid.



There may be something in this. I am sure the badly clogged radiator was responsible for the coolant not circulating properly. It takes a fair bit of pressure to completely blow a perfectly good hose after less than 30 minutes on the road! My idle had been intermittently surging recently and I had assumed it was a separate issue. I think for sure that coolant temperatures were way above what was being indicated on the gauge possibly because of the above and I think that might also have had an affect on the idle. Since swapping out the radiator the idle hardly fluctuates and settles right in at about 900 rpm which is where I like to set it.
 

Fish

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Idaho Falls, ID
My gauges in both my vr4 and my base model sit exactly dead center. The base model we bought brand new in 91 and ever since I can remember that is where it has been.
 

cheekychimp

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Thanks. Sounds as if it is quite possible that the gauge was under reading previously. It certainly does not seem that the under hood temperatures are any higher, if anything there seems to be a lot less heat after opening the bonnet, so I'm guessing the cooling system is functioning better.
 
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