LOWTOX - when all else fails read the instructions-or-have you done/seen this?(long)

[Gary Allan]

Okay ..I got the guinea pig back from the semi major surgery ..and I asked the wrench to spare me some $$ by just putting in water. No problem. So I decided to use a PG type coolant that's available at one of our fine chain stores. AA had LowTox ..so I bought two gallons.

Now normally, in just about every "flush and fill" that I've ever done, I can rarely get more than one gallon into the engine. I do assure that what's in there is just water by running the engine for a good bit with the petcock open and the hose running in the rad. I make sure that the heater (valved) is on ..and that the upper hose is hot/warm.

Anyway, I somehow managed to fit all but two gallons in (I took my time and it took more than usual.

I started getting higher than normal temps. My fan would not cycle when it turned on. I was driving on the highway and glanced at my temp gauge and it was 3/4 of the way up the range (normal in all modes/all seasons is just below 1/2 - if you're at 1/2, you're HOT). When I stopped there was no boil over ...not one sign that there was anything wrong except that the fan wouldn't cycle. No coolant was lost and only a very minor amount changed in the recovery tank due to the fisrt cycle/purge of remaining air. The level was totally stable.

Tearing my hair out I thought of all things that typically effect temp. Now this thing has 170k on it and has surely been in various states of tune ..but what the heck. I ran the on board diagnostics and it showed a bad MAP and O2 sensor. The wrench put on a new O2 sensor and the Mopar site mentioned that a bad MAP can throw an O2 code (always at low voltage) since the O2 is trying to balance out what the MAP is telling the PCM where to put the pulse width on the fuel curve. Okay, new MAP and the O2 code is still there. But if it's in open loop ..the long term adaptives could still be sending it low. Yet, when on the highway ...the temp still rose over time ..especially after the engine fully warmed up (not just coolant) and oil temp reached 180°F.

Still being paranoid of the repair aspect of it (who knows what may have happened - new tb/wp/head gaskets/etc.) I kept looking for something to point there. None seemed apparent.

I then decided to actually read the jug of LowTox. It says that the maximum concentration is 67% (when all else fails, read the instructions).

I drained, cleaned/flushed, and refilled the system with just water. The fan cycled. I then drained the rad and just filled with about 1 gallon of the stuff that I had drained out (maybe a little more). The fan still cycled at idle.

Has anyone else ran into this?? That is, higher than normal temps with no apparent associated symptoms (boil over, etc.)??

 

[XS650]

That's what too high a concentration of anti-freeze does. It has lower heat transfer capability so runs hotter unless your cooling system has lot of extra capacity.

No boiling because the boiling point was really high.

My preferance is to run about 50/50 or less anti-freeze because water is a better coolant than anti-freeze.

Water is neat stuff, I couldn't get a long without it.

 

[Gary Allan]

PG ..at least in the LowTox flavor must have a really high boiling point. I think the normal 50/50 EG is around 235F ...but I must have been pushing some higher temp (perhaps 275+). Although I've got the fan cycling again at idle, I'm still amazed that I was able to get such a profound symptom with just a little unintended overkill. Normally I would have been way too impatient to fit that much coolant in the thing before leaving it to the coolant recovery tank to take care of

Water is amazing stuff. I don't think any other substance has its unique properties ..at least with as many practical uses.

 

[White 03]

The Evans coolant is a PG used without water. I use it in one of my PU's with no problem.

Of course the Evans is designed to be used without water.

I can't figure out why your fan wouldn't sence the high temperature. Could it have been the air bubble caused a hot spot that fooled the temp gauge or cavation at the water pump while the radiator stayed cool?

Also 275 seems high for 3/4 gauge reading. Wouldn't 275 be in the red zone?

 

[Gary Allan]

This isn't Evans. This is LOWTOX (Prestone, I think).

That's the problem, my fan does sense the higher temp. When it turns on, it is incapable of cooling the engine to the point where it would turn off. My highway temps are escalatory at these ambient temps and my fan is running when I'm traveling down the road. This is a guess, since I only hear the fan running when I'm on the offramp ..but it never shuts off once started with this much LowTox in the system. This is something that has never happened before in the vehicles history.

In any event, I drained the coolant ..did a chemical flush ...H20 flush and poured back in about 1 gallon of the drained mixture. The idle cooling after warm up is now cycling ..but still appears to cycle longer than it used to. There's still the issue of the O2 sensor being perpetually low on voltage output .even though it's new. This could be part of the problem on the highway run

 

[White 03]

My mistake, I now see I didn't read your post correctly; fan comes on but won't cycle off. I thought it wasn't comming on. Makes more sence now.