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I use Wetter or Super Collant additive in my cars for at least 10 years because of the Vegas enviroment.
Also try to mix coolant & water so I have the highest boil point. Maybe 60/40.

Don't think it droped the temp 25F cooler like some of the claims.
It might have helped a few degrees.
Hard to remember. Been a long time since I had a temp gauge with numbers in a car.
But it can't hurt.

The temp really goes back to a few things. Engines tend to idle a little warmer like 10F-20F of the T-state.
So the car should idle about 190F-200F without using the A/C.
Under a load is when you need air flowing thru the radiator.
Above 45 MPH they say is plenty of air to cool most cars.
Below 45 MPH fans are needed to cool.
The fans set the upper limit.
The temp can go 3F-5F warmer than the fan 2nd fan set point before dropping down.
A slight delay for the fan to cool the radiator coolant more and it to cool down the engine.

Radiator caps are cheap & easy. They wear out and don't hold as much pressure.
Lower the pressure the easier it boils. Mine started to boil under extremes.
Stock 15lb cap fixed it. But getting back up to the stock pressure found a weak spot in the radiator soon after.
F bodied cars used 18lb radiator caps I believe. Raising the boiling point even higher.
But the extra pressure puts more strain on the cooling system, so 15lbs is fine for me.

Don't forget to run thru some radiator flush fluid and flush everything you can with a hose.
Best if you can drain the block but the knock sencers need to be pulled, & they don't always want to come out.

A bad EGR stuck open would cause it to be lean. Unless maybe it was so lean a cylinder was missing, causing a rich reading.

If after all that work it still runs rich a few things come to mind.
Other tune up parts like fuel filter, air filter, & PCV valve.
Fuel pressure too high, injector, or ignition problem.

Fuel injector cleaner wouldn't hurt.
 

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'72 Eldorado Convertible, '97 Eldorado ETC, '93 Fleetwood
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I use this car for parades and last weekend I watched the temp climb above 230 with both fans running.
We have a member who, while waiting for more fan upgrades on his modified engine, got through a July 4 parade in Las Vegas (i.e., hot weather) by jerry-rigging a couple of lines that drew from a jug and used his windshield wiper pump to spray the radiator on command . . . (My takeaway would be to stay stock in general, but . . . come to think of it, after hunting down the fan clutch when the one on my '72 Eldorado went bad, it turns out that I'm not supposed to have one anyway! I also have the wrong number of blades, bird. But these are low on the list of issues . . )
 

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1996 Fleetwood hearse
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56 Posts
Discussion Starter #23
Yeah I was in Vegas in July. It's a wonder anything cools but it's nothing like Louisiana in July, August, September, well most of the year. In fact I'm heading back to Vegas now.
 

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'72 Eldorado Convertible, '97 Eldorado ETC, '93 Fleetwood
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Those (and Iowa) are brutal; they have that wretched "humidity" stuff . . . I'll take 115F here over 85F in Iowa any time!
 

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1996 Fleetwood hearse
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Discussion Starter #26
Welcome to Vegas KC5MHB.
Bring a jacket. It's a sunny 46F today with a low of 36F tonight.
Just getting this...LOL. Vegas was a little chilly but nice. Stayed at the Linq, saw a couple of shows, walked the strip. I like that the city has cleaned up the sidewalks and limited the number of people handing out escort cards. Visited the south rim of the Grand Canyon and there was snow.
 

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2015 SRX Premium FWD
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450 Posts
The car most likely has a clogged/restricted radiator. Fix the problem first and you won't have to worry bout those other things.
 

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'72 Eldorado Convertible, '97 Eldorado ETC, '93 Fleetwood
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I like that the city has cleaned up the sidewalks and limited the number of people handing out escort cards.
It's not that we haven't been trying . . . it's just that every single attempt was getting blocked in court . . . I suspect that it's not that we managed to stop them, but that the vice squad finally managed to get some convictions that shut down the employers . . .
 

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68 DVC, 96 FLTWD Brgm, 11 CTS Premium (two)
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Neither of my fleetwoods ever overheated (with fans running properly and water pump not leaking) even in the 100F+ temps here in FL in heavy traffic jams.
 

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'72 Eldorado Convertible, '97 Eldorado ETC, '93 Fleetwood
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I suppose I should remember from thermodynamics decades ago, but is a radiator more efficient in humid or dry air?

I guess that is, is heat conductivity higher for humid or dry air?

115F at well under 10% here is common in the summer here . . .

(and then there's Phoenix where you can get 120F+ and well over 50% in monsoon season! :eek:
 

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I suppose I should remember from thermodynamics decades ago, but is a radiator more efficient in humid or dry air?

I guess that is, is heat conductivity higher for humid or dry air?

115F at well under 10% here is common in the summer here . . .

(and then there's Phoenix where you can get 120F+ and well over 50% in monsoon season! :eek:
Cooling is more efficient in LESS humid weather.
 

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1996 Fleetwood hearse
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56 Posts
Discussion Starter #32
So I just made a discovery with the cooling system. Seems that the coolant temp sensor may be bad as it isn't telling the ECM what the actual temperature is. I can unplug it and both fans run so the fans are good but when it gets around and above 230 only one of the fans come on. The A/C fan is the smaller one (someone correct me if I'm wrong) and the larger one the primary. The larger one is not coming on with either the A/C or due to max temp and that has me thinking the sensor is bad. Sounds about right?
 

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Base cooling fans (no cooling option code) = Right 150w, Left 100w
Extra capacity (V03) = Right 150w, Left 240w
Heavy duty cooling (V08) = Right mechanical clutch fan, left 240w
Right fan also called primary fan / fan 1
Left fan also called secondary fan / fan 2

Above 225F (226F) the primary / right / #1 fan turns on (with A/C off).
Above 232F (233F) the secondary / left / #2 fan turns on (with A/C off).
Fans may turn on sooner with A/C on depending on pressure.

Depending on the option code the left of the right fan motor might be bigger.
Off memory I thought all the electric fan blades are the same size, but the motor brackets are different diameter motors.

The right fan primary will come on eventually with it hot enough ideling.
It take a lot to get the feft secondary fan to come on ideling if everything else is working right.

Wouldn't doubt a slight diviation of a few degrees in the mechanical gauge and / or ECM temp sensor.
But you're also reading temp in 2 different locations.
Your mechanical gauge is in the drivers cylinder head.
The EMC temp sensor is in the front of the engine.
You're only showing about a 4F difference.

It's only a 7F difference to get the secondary fan to turn on.
But again normally the 1st fan starts to bring the temp down before the secondary kicks in.

For additional cooling you could probibly replace the 150w primary with a 240w.
Looks like it's an even swap, & elctrical will handle it.
Normally the manufactures used a lower speed fan for primay because they are quiter and may be better for fuel econimy.
But still you would have the stock turn on temps unless you added an aditional temp or mechancal switch & relay.
 

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1996 Fleetwood hearse
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56 Posts
Discussion Starter #34
Swapped the coolant temp sensor just to be on the safe side. So this is how it is working: @226 degrees (per my OBDII reader) the smaller or left fan (looking from the front) kicks on. Higher than about 230 the larger right fan turns on so I know the fans are working properly but that still doesn't explain the bucking at that temp. I can turn the A/C on and the right fan cycles but the left fan stays on all the time. So to compensate and make sure the fans come on a little earlier, I placed a 1K Ohm resister in parallel with the connector which tricks the PCM into thinking the temperature is about 10 degrees hotter than what it actually is and it will make the fans turn on sooner. Yeah I know I'm messing with the computer's ability to be efficient but I'd rather not overheat in a parade. I did swap the wire harness between the fans from my other car as the plug had partially melted on one of the pins so that may have been an issue as well.
 

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In the US (with left side driver)
Drivers side = left side
Pasengers side = right side
The standard is left or right from where the driver sits.

Seems like the coolings fans are operating fine now.

Maybe uninended coniquences with engine tuning by tricking it to read a lower temp.
Cold drivability issues. Hot reduced power & MPG from retarded timing.

Besides that one problem is the engine coolant temp sensor (ECT) is not a linear sensor.
The resistance between two temps is not consistantly the same across the temp spectrum.
For example -40C to -30C is 10C differance and 48k (48,000) ohms apart.
90C to 100C is only 64 ohms apart.

Then factor the parallel resistance.
0C (32F) in your case would be 904 ohms which means the ECM thinks the ECT is about 49C (120F), 88F warmer off calibration.

It's not too costly or hard to add an additional fan control to set the fans to come on sooner.
 

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1996 Fleetwood hearse
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56 Posts
Discussion Starter #36
Update:
Since I've been getting consistent P0402 and p0430 codes, I ordered 2 new catalytic converters since they keep coming up as the likely suspect relating to the codes. So I pulled the driver's side and yep, it is broken into large chunks partially blocking the outlet. Did a little digging and found that could be the cause of overheating and reduced engine performance, not to mention fuel economy.
 

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So I just made a discovery with the cooling system. Seems that the coolant temp sensor may be bad as it isn't telling the ECM what the actual temperature is. .....


Starting at the beginning I kept accumulating regular maint. parts and procedures that could be causing or contributing specifically to the 'bucking when real hot' issue. Most other stuff was being mentioned, but I've learned from a friend's painful experience with no start / hard start / phantom dying (for almost a year) that I kept that sensor in the mix of culprits. Every 1/2 year or so I'll think to open up the in-dash reader to check for history codes or anything else interesting. One amateur thing I always do to check the WP sensor is to compare its temp. v. the PS head sender for the expected temp. differential between the two.

Also of late there's been growing chatter on another forum with poor or dying operation leading back to IC/ICM. Mayhaps just a hallmark for those parts getting 25 years old. So add 2 more things in the 'regular maint.' column. And I read that you changed the sensor = good deal. But I'd treat the car to a new cap and thorough EVAP checkup too for no particular reason.

And thanks on the busted up cat. I had not been catching where that's gotten to be an issue on our cars.
 

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Congrats.
Looks like you found the problem.
Restricted converters will make the engine run hotter.
Plus the car will loose power as it gets hotter & more exhaust is backed up betweent the engine & converters.
It can get so bad that cold it will seem fine but on the highway it will slowly have reduced power while the engine is struggeling until almost nothing.
 

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96 FWB
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......... I did swap the wire harness between the fans from my other car as the plug had partially melted on one of the pins so that may have been an issue as well.
A few months ago within a short time on the '96 with just 70k a tiny hidden leak progressed to failure and turned out to be the front (hidden side) of the sidetank. After replacing it and doing the 'sensor pulled plug test' the PS primary did not come on at all. It felt a little stiff but the real cause was the burnt plug. I had already replaced the 240w DS secondary 3 years ago because I didn't like the way it free-wheeled. In addition to 20+ year old plastic the non-operating primary may have stressed the radiator to otherwise premature failure.

Cliffs: I'm doing simple static and live tests plus maint. replacement(s) even more frequently now.

ps - there's simple Metri-pac ends if you want to repair that other harness.


578100



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1996 Fleetwood hearse
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56 Posts
Discussion Starter #40
UPDATE While the cat on the driver's side helped keep the car cool, it still had issues with the engine bucking, almost like a misfire but with no codes. It was in a 1.5 hour parade at 2 MPH and did fine for the first 1/2 or so. Kept watching the temp on the gauge and via my OBD reader on my phone. It progressively got warmer and warmer( started off going to around 210 then it'd cool off, then 213 and finally 226 and it stayed right around that) even with the A/C running the primary fan the whole time. It stopped at 226 and hung around that but still bucked. I'm going to replace both the thermostat and the water pump, including all fluid and have the radiator flushed. I think either the thermostat is sticking or the water pump is not performing as it should. In either case, that should solve the issues I'm having.
 
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