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I agree personally I would strive to stay near the PH of 50/50. Testing is in order and that tester is on my list once they email me that it will work.

Pre-1995 - DTC codes OBD1  >>

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Still very busy fixing head gaskets and Cadillac's in general. I have had 2 05's Northstar's in a row, one had loose head bolts and another with only 75K the head gasket was eaten alive by Dexcool. Th

I've heard anecdotes about Dexcool and other OAT-based antifreezes. But just about all manufacturers switched to OAT anti-corrosion coolants in 1995 and the rest soon after, and none have gone back t

In the end, if your going to use Dexcool, change or flush the system every 2 years. Green coolant on the other hand should be good for 4 years.

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Nitrites are used in diesel engine coolant - I don't think they're in passenger coolant and you don't want them in passenger car coolant.

In the case of Dexcool, the organic acid corrosion inhibitors do not deplete over time but the coolant can get acidic so I would think pH would be the be the parameter I'd want to monitor but then again, it is easier to drain and refill every couple of years vs. trying to save a few bucks on the cost of changing the coolant.

The ones on the list that I looked into would work for automotive antifreeze as well as diesel antifreeze. They had a fork in the road in interpreting results for different types of antifreeze.

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Ok, Cole Parmer's Pre-Sale department just got back to me, that PH meter above can be used for coolant with an electrode,

Electrode - $77

http://www.coleparmer.com/Product/pH_electrode_double_junction_epoxy_body_BNC_direct_connection/EW-35804-08?SearchTerm=35804-08

PH Meter $117

http://www.coleparmer.com/Product/Oakton_pHTestr_10_Waterproof_BNC_Pocket_pH_Tester_35634_14/EW-35634-14?SearchTerm=35634-14

Now the only question is, once we know the PH of 50% Dexcool or green, at what PH do we immediately change? Kevin has concern that a PH of 10 is too far off neutral toward base. More research necessary.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Knowing what the minimum pH specification is the key piece of information. Without that, you don't know if the tester has enough precision to even do the job. For instance, say the minimum pH is 6.5 but the tester only reads to an increment of 1, the tester wouldn't be able to do the job properly because once the tester read 6.0, the coolant would be too acidic.

Once the minimum specification is known, the tester should be able to read within 10% of the range of the specification in order to be considered precision enough to monitor the coolant.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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According to the specifications the tester's PH range is 0 to 14 with an accuracy of + or - 0.01 PH with a Resolution (pH)0.1/0.01

That last spec of 0.1/0.01 is confusing.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

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It seems that the worst case is a resolution of 0.1 pH, which is OK. The dual number should be explained in the fine print. I would think that around neutral, say pH from 4 through 10, the resolution is 0.01 pH, and coarser outside that.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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+/- .01 on the pH is definitely "precision enough" to monitor the coolant but without knowing the minimum pH value, I wouldn't buy the equipment.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Ill contact the sales person and ask

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I didn't find anything on pH levels of engine coolant on a quick web search. I would think that anything much below 7 is acidic. The anti-freeze compounds are all buffered for mild alkalinity and when that's gone, it's time. Let's see what BBF turns up.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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From an Amazon page (click image to go to the page). Note the pH vs. test strip colors on the bottle.

61tYXeAJqlL._SL1500_.jpg

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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+/- .01 on the pH is definitely "precision enough" to monitor the coolant but without knowing the minimum pH value, I wouldn't buy the equipment.

Kevin are you speaking about the minimum Ph value of the coolant? Or are you speaking about the testers threshold of accuracy?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I've been looking at user reviews of automotive coolant test strips on Amazon and find these issues with test strips:

  • Test strips are very sensitive to atmospheric contamination.
  • They have a limited shelf life, typically two years. The ones that are shipped to you may not have two years left.
  • They are sensitive to the temperature of the coolant.
  • They can be thrown off by strange contaminants.
  • Accuracy for coolant concentration is poor except near 50-50.

The key parameter for corrosion is pH. I've seen people that represent themselves as chemists say that the best thing to do is get a hydrometer for antifreeze concentration and a cheap digital pH meter for anti-corrosion life.

There is a huge selection of small pH meters out there but the vast majority are for gardening, brewing, or medical use. BBF has a better solution (no pun intended!).

Hydrometers have these issues:

  • The temperature of the coolant is a factor in specific gravity.
  • Hot coolant can throw off the specific gravity reading of some hydrometers. Get the all-glass float type to avoid this.
  • The smaller ones are hard to use because bubbles stick to the float, and that will cause it to read higher fraction of antifreeze.

I think a good hydrometer, properly used, is a perfectly good tool, and they are available at better auto parts outlets. The GM FSM's recommend a refractometer to measure coolant concentration (and battery condition). The manuals use a Kent-Moore special tool, J26568, which goes for about $320. There is one on Amazon for $28 that seems to be an exact equivalent (click the display illustration to go to the Amazon page):

51OVEF74TvL._SX385_.jpg

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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+/- .01 on the pH is definitely "precision enough" to monitor the coolant but without knowing the minimum pH value, I wouldn't buy the equipment.

Kevin are you speaking about the minimum Ph value of the coolant? Or are you speaking about the testers threshold of accuracy?

The minimum pH value as a design specification from GM - at which pH does the coolant begin to harm the engine?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thanks Kevin. Here is an article that specifically mentions the Northstar and the Ph of Dexcool being lower than green (who knew) but again, no mention of what Ph level is considered a red flag. I may call the dexcool manufacturer and see if they have any guidelines for acceptible Ph ranges

Jim they mention the hydrometer in this article also (but a cheap one, not a refractometer) the guru spoke about the importance of a good refractometer.

http://www.cartechbooks.com/techtips/antifreeze

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I think that an inexpensive Pep Boys hydrometer is OK if you are careful how you use it: room temperature coolant, no bubbles on the float, give it a little time to settle down, and understand that the results are approximate. The sweet spot for antifreeze is fairly broad, 50% to 70%, so if you get a cheap hydrometer to read, say, 60% you are good.

But for $28 I would get the refractomer, just because the FSM says so, if I was going to be doing a lot of cars or wanted really good accuracy. For just one or two cars, checking annually or when refilling antifreeze, the Peb Boys turkey-baster-with-a-bubble hydrometer should be enough.

The pH level on the bottles of the test strips put the line between good and bad at pH 6.5, about what you will read with distilled water (not exactly 7.0 because there is always some CO2 from the air in it). To someone that is conservative in auto maintenance, I would go with 7.0 as the line, or even 7.5 because coolant is cheap and engines are expensive. From looking at several test kit vendors and their ranges of pH for engine safety, whatever GM recommends, it's going to be between pH 6.5 and 7.5.

The accuracy of the strips is apparently a pH change of 0.5. Note that test strip accuracy is limited by the time since manufacture and exposure to air, etc. The pH meter will have instructions that come with it that tell what its accuracy and limitations are and how to prepare it for accurate use. If its accuracy is a pH change of 0.1 or finer, it's going to be more accurate than any test strips, and, used according to instructions and occasionally checked with a test solution provided by the manufacturer, you will be able to trust it for the safety of your engine.

There are cheaper pH meters but all the ones I found on Amazon were for brewing, cooking, commercial food preparation, horticulture (soil monitoring), hydroponics, etc. I didn't see one focused on automotive coolant, but didn't spend a lot of time. BBF's swimming pool pH meter seems more than adequate for the job, and if a little pricier than the cheap throwaway things I saw on Amazon, is more likely to survive and prosper in a working shop.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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In the end, if your going to use Dexcool, change or flush the system every 2 years. Green coolant on the other hand should be good for 4 years.

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Haha.....that is true barczy01, but being a numbers guy and given that I maintain 7 Northstars right now, I like being able to easily know what is going on. Iv bought 4 Northstars in the last 6 months, besides checking for combustion by products, I can test the coolants Ph easily to give an indication of the engines maintenance

I have a call into the Ph tester sales to get them to clear up the accuracy and I plan to call Dexcool's Tech Support to ask them about what an alarming Ph would be.

I have a feeling that Dexcools tech support is going to refer me to GM to determine what a red flag PH would be

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Jim, this is not a pool PH tester, I have sent the company a note to see if it can be used for pools, but I dont see why not. This is a description of the company that makes the tester:

Since 1955, Cole-Parmer has been a leading global source of laboratory and industrial fluid handling products, instrumentation, equipment, and supplies. We are proven experts in the fields of temperature measurement and control, electrochemistry, and fluid handling.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I spoke to Cole Parmer's Pre-Sale department this morning and the spec of 0.1/0.01 on their web site is wrong, it should read 0.01 PH accuracy for this PH tester which is good. In addition this tester can also be used to test pool PH as long as it is rinsed after testing coolant.

Spoke to AC Delco's tech support area regarding normal and red flag PHs for Dexcool and they punted to the Dealer.....Called the local Cadillac dealer and asked for the Service Manager and was on hold for 20 min and gave up. It is Monday so its understand, but I do not expect the dealer to have this info, they will cite the 5 years/100K miles stuff no doubt. Ill keep trying to find a red flag PH but it does not look optimistic.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Going by what I found from multiple, test strips people, I would go with this scale:

pH 6.5 or lower: DRAIN IT RIGHT NOW!

pH 7.0: Drain it ASAP.

pH 7.5: Schedule a coolant drain/refill.

I think that a sticker would be good on the surge tank that is renewed when you change or flush the coolant, and has a table of pH measurements with dates, and possibly a second table with specific gravity or antifreeze percentage measurements with dates. Even if you have just one aluminum engine it's good to have. A glance can tell you if someone put water in the system or there is a change in the pH, and you can tell how much longer your coolant has to go before it needs refreshing.

Note that it's hard to find an iron engine out there anymore. Even in an iron engine, acid coolant is not a good thing, and aluminum components like radiators, thermostat housings, etc. have been common since the 1960's.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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That is good info Jim thanks

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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In the end, if your going to use Dexcool, change or flush the system every 2 years. Green coolant on the other hand should be good for 4 years.

Since there are not any block drains on a Northstar engine, it is impossible to get all the coolant out of the engine and it can then be a real pain to get the coolant back to 50/50 concentration. That is one reason the guru used to say just to drain as much as you can and refill with fresh Dexcool mixed 50/50 with distilled water every 2 to 2-1/2 years or 100,000 miles whichever occurs first. Unless you flush with distilled water, minerals from tap water will be introduced into the system.

Most "green" coolant these days is silicate free coolant but if traditional green silicated coolant is used, no way would I let that go 4 years. It would get drained and refilled every year.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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The FSM says drinking water quality is what is required for the cooling system. If you are going to monitor the pH and the percentage of antifreeze, I would be OK with the tap water.

The method I used for last-century-iron-engine coolant refills, flushing with tap water and topping off with pure antifreeze, seems to be a reasonable approach for a Northstar - except that nowadays people don't like you draining your radiator into the storm drain. Certainly drain it without a hose into a can that you can take to the appropriate faculty for proper disposal. I don't have a reasonable way to deal with the gallons and gallons that are involved in flushing it while idling.

The pricey but near-ideal coolant that BBF turned up is intriguing. The main things I can think of about it are that you really want to make sure your cooling system is in top-notch shape before you switch, to minimize the possibility of a leak or having to deal with a repair while that stuff is in the car, And, you might want a spare gallon in the trunk for road trips to avoid any possibility of needing to add water if there is a leak.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The FSM says drinking water quality is what is required for the cooling system. If you are going to monitor the pH and the percentage of antifreeze, I would be OK with the tap water.

The method I used for last-century-iron-engine coolant refills, flushing with tap water and topping off with pure antifreeze, seems to be a reasonable approach for a Northstar - except that nowadays people don't like you draining your radiator into the storm drain. Certainly drain it without a hose into a can that you can take to the appropriate faculty for proper disposal. I don't have a reasonable way to deal with the gallons and gallons that are involved in flushing it while idling.

The pricey but near-ideal coolant that BBF turned up is intriguing. The main things I can think of about it are that you really want to make sure your cooling system is in top-notch shape before you switch, to minimize the possibility of a leak or having to deal with a repair while that stuff is in the car, And, you might want a spare gallon in the trunk for road trips to avoid any possibility of needing to add water if there is a leak.

What?!.... Have you seen what water with a high mineral content does to a cooling system? pH is only ONE process parameter in the cooling system process. With all due respect, just change the coolant every 2 or 2-1/2 years and be done with it - it's not worth re-engineering the lifecycle of the coolant.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I have always used distilled water and because of the guru I never flush the system because of contaminating the system with minerals.

In the old days as Jim notes we used to flush the radiator with a hose running it till it ran clear. But that was the old days

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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