overheating is back

[zadam123]

Good to hear zadam.

And for what my opinion is worth, the shop that told you the heater core has nothing to do with the A/C system was correct. The only way the heater core can be used to aid in cooling is when the engine is running hot and the heater is turned on.

ok im curious now. i bought the car new and know what has ever been done to it, if my car overheated and heater core was replaced, do they have to add freon to it, maby they had to take off a freon line to do the heater core?

if not how can i get to much freon in the system?

it worked untill last summer and only things done to the car were heater core,theromostat and clutch fan

[RickOKC]

if not how can i get to much freon in the system?

Sometimes people will just blindly dump "X-amount" of refrigerant into the system instead of using using gauges to add what is actually needed.

[Y33TREKker]

ok im curious now. i bought the car new and know what has ever been done to it, if my car overheated and heater core was replaced, do they have to add freon to it, maby they had to take off a freon line to do the heater core?

if not how can i get to much freon in the system?

it worked untill last summer and only things done to the car were heater core,theromostat and clutch fan

Only the shop that replaced your heater core would know whether they broke open the A/C system in the process, but normally, they shouldn't have had to. The A/C system is a closed/pressurized gaseous system entirely separate from the heater core/radiator water-filled system.

If they did add freon to your A/C system when they were replacing your heater core thinking for some reason that it would help with the overheating problems you were experiencing, it's like RickOKC said, maybe they didn't properly use/read the gauges made for working on A/C systems and simply overfilled/over-pressurized the A/C system.

We can only speculate on what may have happened and who may have done what, but the important thing is that it sounds like your VX overheating problem has been solved.

[VX KAT]

following this closely as had 2 overheating episodes in a month.

Both around 95 degrees, A/C on , going slow on a trail. Was OK for about a mile, but when I stopped...temp needle maxed. Turned off A/C, heat on max, drove faster on trail...temp came back to normal within a min or two. No doubt due to A/C, air temp, slow speed.

I figure my Kilby skids must prevent some heat from escaping, plus my VX is carrying a fair amount of extra weight full time (tires, skids, sliders, roof rack, cargo basket, f/s spare, hitch, superbumper, JAMAS boxes....and the 2 plastic skids.) That's about 450 lbs.
So that's like 2 real good size passengers..... should be OK I'd think..... Dub probably carries about 1000 lbs freight on board! ....

I have Purple Ice in the coolant which claims to reduce temp a few degrees. With the extra demands I'm putting on it, and the full skids, figure a radiator functioning at peak efficiency would be a really good idea. Since I don't know service history, I'm thinking of doing what zadam did...having radiator prof cleaned.

Could a cleaning/backflush create leaks, similar to when you switch from dino to synthetic?..i.e. cleans out crude that's actually plugging a hole?

Thoughts, suggestions, recommendations?

p.s. pbkid prev suggested cutting a few extra holes in the skids to vent heat, with a backward facing cupped cover (to prevent getting hung up)....but that will cost bigger $$$.....

[JAMAS]

I am not a pro, but I believe coolant does loose its effectiveness overtime. A flush and refill every so often is a good thing.

[vt_maverick]

Sue did you read the post about the aluminum radiator? Probably not cheap, but if you consider your extra heat-generating / trapping mods as permanent, maybe it's a good idea to approach the solution to your intermittent problem as a permanent cooling mod as well?

http://www.vehicross.info/forums/showthread.php?t=20866

[rsteinmetz70112]

I am not a pro, but I believe coolant does loose its effectiveness overtime. A flush and refill every so often is a good thing.

I don't think that is correct.

The major constituent of most coolants is some form of glycol, although there are other chemicals used. It does not break down chemically in a sealed cooling system, it will breakdown in the environment.

What does break down are various additives that inhibit corrosion. It also gets dirty.

[VX KAT]

darn....I think it's official, I've got an overheating issue, now occurring every time I drive...

Just reviewed this thread and pulled out all the various things mentioned as possible culprits:

• Broken head bolt
• Head gasket
• Thermostat
• Stuck thermostat
• Radiator cap
• Sensor that turns fan on/off
• fan clutch
• Heater core
• Water pump
• Radiator obstruction
• Anti-freeze mixture

Printed out "newthings" recent thread on the custom Ron Davis aluminum radiator too......http://www.vehicross.info/forums/showthread.php?t=20866

Called up my mechanic to make appt...first thing he says is why don't I put in an aluminum radiator....hmmm...now there's an idea......

OK, gonna look into details of the Ron Davis radiator...gulp...and see what kind of moula I'd be talkin' here...gulp....also asked newthings for detail$.

After I faint, and dave revives me, I know I'll have to have my mechanic explore some of the "other" possible culprits.

Since my heat-adding mods are basically "permanent", this aluminum radiator really does make good sense......that's my story and I'm stickin' to it!

[Scott Larson]

Stuck thermostat. Open or closed, it doesn't matter. If it's closed, water can't circulate. If it's open, water circulates too much, too fast and can't pull the heat away. The fact that it just suddenly started overheating is the clue IMHO. Faulty rad cap is also a suspect in this hot mystery

[gergmon]

Sue I've been having the exact same problem too. Only when I use the A/C does it start to shoot up after about 10 minutes. I look forward to hearing what you find out!

[IndianaVX]

Agree with Scott, you can have new radiator, shiney new cap, the prettiest new hoses, ect..... But if the thermostat isnt working right, none of that new stuff will cure your problem. Maybe it's just me, but I always start with the little (read cheap) stuff first. And these cheap things probably needed replaced anyway. Are you Loosing coolant? Also check the firewall between brake booster and fender for coolant. I've seen my truck spray coolant thru the resivour cap.

[VX crazy]

Mine does it too, and so did my other vx in the Texas heat with ac on in stop and go traffic, I just turn ac off and sweat til I start moving. Funny thing is the temp gauge in the truck says normal or tad over half when scan gauge says 210 , but after it gets just 6 degrees warmer the needle shoots way over, I have let it get to 222, too hot for me, no leaking coolant, coolant new in last yr and half and royalmpurple wetter always used too.

[VX KAT]

OK, gonna look into details of the Ron Davis radiator...gulp...and see what kind of moula I'd be talkin' here...gulp....also asked newthings for detail$.

After I faint, and dave revives me, I know I'll have to have my mechanic explore some of the "other" possible culprits.

Agree with Scott, you can have new radiator, shiney new cap, the prettiest new hoses, ect..... But if the thermostat isnt working right, none of that new stuff will cure your problem. Maybe it's just me, but I always start with the little (read cheap) stuff first. And these cheap things probably needed replaced anyway. .

Yeah, absolutely, going to have mechanic start next week picking off the possibilities (based on his eval and what he suspects). I'll also discuss various options with him re: radiator flush, alum radiator, etc...


1) Drove it for last 2 days up the big hill, with A/C, NO overheating at all... but AIR temp was at least 6-8 degrees cooler....can that small of an air temp variation 6-8 degrees (91 vs. 98-99) really make a big difference??

2) Talked to "Bill" today at Ron Davis Racing Radiators. He wanted to ask about some things about my VX before he finishes the design updates (from "newthings") on the aluminum unit.
He had me try some stuff:

• evaluating how far the fan blades protrude beyond the shroud (toward the rear of truck). The top of the shroud is a little deeper, for finger protection, but the sides are a little shallower.
  My fan blades BARELY break the plane of the shroud.....meaning, my fan blades are set well INTO the shroud. Bill said that set up moves LESS AIR.
  WHAT DOES EVERYBODY ELSES VX LOOK LIKE IN THIS REGARD??
  COULD THIS BE YET ANOTHER "HAND MADE" VARIANCE??

• moving the OEM main fan blades manually, feeling for resistance, when cold and when hot.
  We found it spun pretty well, even easier when engine was warm
  

• We checked to see if all bolts holding the radiator were tight and flush, with no spaces - checked ok.

• Dave and I already confirmed the A/C fan comes on appropriately.

• He asked if everything appeared to be OEM...he STRONGLY recommends ONLY OEM parts such as the blades, shroud, etc... He feels they're properly engineered for the vehicle, have certain tolerances, and are more durable in general.

• [*He advised the OEM mechanical fan can move MORE AIR than a twin electrical fan set up can, so he recommends we keep the OEM....and make sure it's functioning optimally.
  Is there a spec on the fan blade placement?.....gotta look that one up in the big manual.

Any comments, input????
.
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[Triathlete]

Sue...your vx is just too clean. The dirt keeps the sun from heating things up...see, there is a method to my madness!

[Zu4two]

Sue, I looked at my fan last night and it's relation to the shroud. Mine protrudes about 3/4" at the top. I don't know how you would modify that clearance, maybe someone put washers in-between the fan and the clutch. You mention that the fan moves easier with your hand when warm? When it gets Hot it should actually be harder to move since the thermostatic clutch should be engaging. Of course this is when measuring resistance with the engine off. It is not recommended to check this with your hand while the engine is running

Have you checked to make sure you don't have wax residue clogging the radiator fins from your incessant detailing? All kidding aside, a good power washing of the radiator might rid it of excess dust and grime that builds up after time.