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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
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280 Posts
Discussion Starter #101
Yea,, but remember, it's got no antifreeze in it, just straight water under pressure at 240+ Even with antifreeze, when they overheat severely, the coolant makes all kind of noise after shutdown. I still think its headgaskets too, but I'm STILL, not convinced. I only ever checked the purge line flow, when it was cold. I think, I'll ck it after it's got hot, n see if it's still flowing.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,417 Posts
I thought that you posted about shooting the hot purge line with the new IR thermometer ? Post #41.

Severe overheating will cause noises in the surge tank - from the water boiling off of some engine cooling system hotspots. Water, even at 16 psi, boils at 250.

If the heater core circuit is not flowing "solid" coolant then I'd guess the purge system is not, either.

We've been at this for 3 weeks now, taking potshots in the dark, and appear no closer to a fix than on Day 2.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,250 Posts
If you have gurgling and bubbles in the surge tank, no heat from the heater core and a 240° temperature, I think it is a pretty safe bet that a HG has failed.
======================
I would agree with failed HG's -
EXCEPT - he claims to have a clear and flowing purge line
and passed the block test with no color change of the blue fluid -
that just can't be -
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
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280 Posts
Discussion Starter #105
Hallelujah! It's fixed! After the kid (friends son Jon, who I gave the car to) came over this mrng, after it stopped raining, and after he he helped me rescue a round hay bale out of the ravine, with 300' cable n tractor, we walked by the car, after putting tractor up, and I said, "Let's check this xpansion tank, n see if it went down any" I let it heat up to well over 240, after raising the idle enough to thoroughly heat all the coolant, with the tank full to the brim, last nite, with the thought that maybe all that churning water(no antifreeze) might clean out something in the heads, maybe. Well, the tank had gone down well over half way, I put bout 3/4 gallon in it, started it, and we had defrost heat straight away. Let it get to 212, then 216, raised the idle n it came back down. Came back to 212-214, but ddnt keep climbing, like it has been. So, I shut the hood, got in it and blasted down the road. Temp came all the way down to 190m by the time I went 2 miles to the end of the road n back. Stayed there. I romped it hard on the way back, let wind out some. It just just cooled more. Was 190, when I pulled it back into the yard. Next weekend, I'm gonna put the big blue tub under it again, pull the bottom hose, n see what, I hope, we boiled out of it. When I shut it down at 240, last nite, it was really churning for a little while. It acts like it always used to, now. It hasn't run this cool in over a year. I know this car, and it never used to ever get hot, at all. Thanks to all you guys, who were patient, and gave me lots of ideas, it helped a lot. Man, I'm glad its fixed!
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,417 Posts
Air lock(s), probably heater core and/or heater circuit at the water pump cover. If you drain it again know that the cooling system, dead dry, takes about 15 quarts of 50/50 coolant. Which coolant you use is up to you, but religiously exchange it every 4 years or a tad earlier.

I would strongly suggest that, given your recent cooling system troubles, you have the new 50/50 coolant installed by a good local Mom & Pop shop using a vacuum/pressure coolant machine. Then you won't need to go through this drill again. Besides, they'll exchange ALL the coolant - there are no block drains so 3 - 4 quarts of old whatever remains in the engine. NO TABLETS !!!!! NO SNAKE OIL !!!!

Thanks for the feedback.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
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280 Posts
Discussion Starter #107
Thank you Sub! Good to know bout the 15 at capacity. No chance for local shop doing a refill. Very limited here. I thought about air lock/trap too. But, with all the driving, at least a year, is that still possible? And purge line always flowing? Isnt that one of, or its, purpose?
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,417 Posts
Speaking for the Northstar cooling system ............

ANY time that engine runs the purge line should flow a steady stream into the surge tank. ANY time. ANY rpm.

If bubbles or partially vapor (as opposed to "solid" coolant) gets to the water pump it stops pumping. The purge system assures solid coolant - if it's not fighting a bad head gasket or cooling system leak.

Yes, airlocks are possible any time - and one can be a real bitch to clear out in the Northstar - as you have discovered. Which is why we have been harping on flow, purge line, and hose temperatures. One of the first indicators of airlocks is no or little cabin air heat.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
Joined
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280 Posts
Discussion Starter #109
That's what I dont get, xcept for that time Saturday, it's always had good heat. He says it had good heat all winter.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
Joined
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280 Posts
Discussion Starter #110
I'm thinking, maybe, after it sat for several months, then I gave it to him and the radiator started leaking, so I put a new one in for him, and at that time I put more Gm Sealtabs in it, on top of what I already had in, from when I had it, and it was after that, it just got hotter n hotter. I'm thinking, MAYBE, the too many Tabs, clogged up one or both head cooling passages, and they mite have boiled out last nite, when I shut it down at 240+, full to the brim, with the cap on tite. I'm gonna put my big blue plastic tub under it, next weekend, to see if I can catch anything when I pull the bottom hose to try n confirm this.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,417 Posts
If you do that you might want to limber up the air compressor again and blow out the heater circuit. Simply dropping the lower hose on a Northstar gets only about half the coolant out.

As I posted, then you get to go through the entire bleed and purge exercise again.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
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280 Posts
Discussion Starter #112
According to my IR thermometer, the defrost was putting out 130 degree air. I only want to let out enough to add enough concetrate, for a 50 50 mix. Will the bottom hose pull off get me enough release to add 7 1/2 qts, you think? I'm gonna add thru the top hose, to prevent any air locks.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,781 Posts
WOW! I've never heard or seen one clogged that bad (if that is what the problem was). Those tabs serve a purpose in the right situation, but this sounds like too much of a good thing.


Will the bottom hose pull off get me enough release to add 7 1/2 qts, you think?
No, look where the lower hose attaches to the radiator. It's only about half way down. You will get more (maybe a gallon and a half) out by opening the drain valve. Might even want to consider connecting a garden hose to one of the heater hoses and flush the system like that once or twice,m then add a stronger concentration of coolant to compensate for the water in the system.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
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280 Posts
Discussion Starter #114
Oh, is that what Sub meant, I can flush the heater core back thru the radiator?
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,417 Posts
No, you connect the hose to one of the heater inlet/outlet pipes. Most of us have oddball pieces of hose with an array of fittings to adapt them to garden hose. Some fittings and couplers on the HELP! racks at parts stores.

What does the water in the surge tank look like right now ? Clear or dirty/cloudy ? If it's clean and clear you might be better off simply draining as much as you can, then filling with straight coolant, driving a half hour, check coolant concentration in the surge tank with a cheap coolant tester hydrometer. If it's too low in concentration, wing it and drain some more and refill with raw coolant. Anywhere between 50/50 and 70/30 coolant/water concentration is good. GM recommends 60/40 and 70/30 for extreme duty anyway. Past 70/30 is no good - boil points get lower in temp and freeze point rises in temp. Post #83.
 

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1999 Deville base
95 Eldorado, 99 Deville, 05 CTS
Joined
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280 Posts
Discussion Starter #116
Ok, yea, Idk, bout color, looks really clear, but hard to tell. I fgt anyway, that that Blue Devil cleaner is still in there. Gonna have to flush the whole thing out, AGAIN. I'll have to take the tank out, to get to heater hoses, to back flush.. Am gonna try n capture everything that comes out of everywhere in an attempt to see if it was airlock or clogged pellets. It irks me to no end, not knowing exactly what happened, not just for curiosity, but for future reference. I'm sure others would like to know also. Im gonna strictly measure what goes back in, to 15 qts, going back in also. Thanks Sub, and Ranger, and everyone else! Man, I was almost jumping up n down, yesterday, after that test ride, and it was back to super-normal! About time!
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,781 Posts
Im gonna strictly measure what goes back in, to 15 qts, going back in also.
Don't worry about that. Just drain and refill to about 2/3 full. Take it for a ride and then let it cool down. Then check the level and top off as necessary (it almost certainly will go down). After the first time, just fill to the proper level (about 1/2 full). You may have to do this 2 or 3 time before it stabilizes.
 
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