: 97 ETC overheating questions



bobvondutch
05-20-04, 07:21 PM
OK, first I want to thank everyone for the tips:) , although I hate to think about the cost:crying2: of the repair, but I just love this car:bouncy: . Anyhow, I have reserved myself to the fact that the head gaskets need replaced. I have to get the manuals (any good sources), and a timesert kit (anyone selling?), and probably some odds & ends tools, and have a 10-day shutdown at July 4th to do it in. HOWEVER, I do have some more questions.
1) Other than replacing the head gaskets, doing the timesert thing, and a new water pump, based on anyone else's experience, what else?? Lower gaskets (and I do have a small leak somewhere), main bearings, rod bearings, ?:bonkers:
2) For those who have done this repair: how have you driven your car since, and have you had any additional problems? Do you baby it, or use all 300 horses to play with? :confused:
3) Being an engineer and machinist, I believe the head gaskets fail because of the heat cycling of the dissimilar materials: aluminum block/steel head bolts eventually causes some threads to give way, causing the gaskets to give. Anyhow, does anyone feel that the timeserts will eliminate this problem for good: does the use of timeserts make it darn near impossible for the head bolts to pull again??:hmm:
Finally, it seems Bbob is a plethora of information, especially from reading other threads, and I humbly thank him for his help.:worship:

eldorado1
05-20-04, 08:14 PM
1) Other than replacing the head gaskets, doing the timesert thing, and a new water pump, based on anyone else's experience, what else?? Lower gaskets (and I do have a small leak somewhere), main bearings, rod bearings, ?:bonkers:
Lets see... Refill it with the standard green coolant... It's up to you if you want to reseal the lower case halves... I myself am not sure how much work that involves. I believe if it's below the oil manifold, it'd take like 30 minutes to do, but if it's leaking above that, you have to pull the main bearings (girdles?) apart, which is more labor intensive...



3) Being an engineer and machinist, I believe the head gaskets fail because of the heat cycling of the dissimilar materials: aluminum block/steel head bolts eventually causes some threads to give way, causing the gaskets to give. Anyhow, does anyone feel that the timeserts will eliminate this problem for good: does the use of timeserts make it darn near impossible for the head bolts to pull again??Pretty much - CHRfab says after you put in the timeserts, you're free to remove/replace the heads as many times as you want, and it'll be just fine. It's a permanent solution.

bobvondutch
05-20-04, 09:43 PM
Oh yeah, I forgot something!!:banghead: I read up on the removals that other people have done - I take it that since the radiator/condenser comes out, that that AC needs recharged when done. Correct?? Anything else that I should replace while I have the damn thing out - I intend to keep this car a long time, hope to repaint next spring. Thanks guys.

zonie77
05-21-04, 12:56 AM
It will need to be charged again but since it's 134 it shouldn't be a major issue. Do you want to do it yourself?
I did two of them. One has thousands of miles on it, one was recently finished. No further problems. I would think the timeserts are close to permanent. The engine will be dead before the timeserts pull out.

I did both by dropping out the bottom and think that's the easiest way. You don't have to open the brake lines and it's easy to work on the engine once it's out. It would be easy to pull the engine from the cradle once it's out too if you want to reseal it. The guys that have pulled them out the top comment on how hard it is to get bolts out etc. Much easier to drop the cradle!

bobvondutch
05-21-04, 01:14 AM
Zonie:
I had read your posts from before, how do you think I got the guts to do this?? I feel pretty capable of doing all this, except for the AC. Your opinion on resealing?? While I think I have a leak, I have to pressure wash the whole thing, run it for a couple of short trips on dry highways, then see if anything is coming out anywhere. I guess I want honest opinions - if it's not leaking now, but I have the thing out, should I change whatever: I hate to do things twice!!! Thanks for all the info.

Lawrence
05-21-04, 02:17 AM
I would do the reseal while out. It does take a few hours to do but it is nice to have a dry Northstar. And as long as you are considerate of cleanliness should have no problems R&R'ing it. Just be sure to install the main bearings back to their original locations, lined up correct, make sure the backs are dry, and use assembly lube on the crank journals. You'll need the oil manifold, oil pan gasket, rear main, and lower case half seals (2). Use anerobic sealer on the case half, oil manifold and oil pan. Maybe a timing cover seal and front seal. You can reuse the main bearings. Do not remove the rod bearings unless you replace them.

You'll likely need new intake gaskets (at least the ones that contact the head), water crossover gaskets, exhaust bolts, oil filter housing O-rings, oil line O-rings, flywheel bolts. Might do at least the rear valve cover gasket while out.

The time serts are supposed to be a permanent solutuion. If you get a used timesert kit be sure to use only the recommended thread locker, Loctite 266 and be sure to use plenty of cutting oil and take it slow. Use OEM head gaskets. Make sure all surfaces are clean and dry of oil before assembly.

If you remove the engine from the top you do not have to break the AC or ABS/TC. You will have to seperate it from the cradle anyway to do the re-seal.

Also replace the HVAC cover and service the evaporator while the engine is out. Plan on re-wrapping the wiring harness while the engine is out as well. Both of these items deteriorate with age. dloch also covered his HVAC box with some additional heat shield as well. Might be a good idea to have the inner metal box on hand as well, mine was rusted through.

If you don't have one already buy the GM/Helms manual, www.helminc.com There are instructions for removing the engine from the top or bottom. Also all the torque specs and so forth.

You'll need only basic hand tools for the job, including a 4" 3 jaw puller & 12mmX85mm bolt to RR the Harmonic balancer, pulley puller set for the water pump pulley, a good assortment of 1/4" and 3/8" wooble extensions and deep well sockets for the exhaust manifold, a telescoping magnet for the TQ bolts, a torque to angle gauge and of course good torque wrench's.

eldorado1 made a mistake with regard to the "green coolant". Don't use it. Use only Dexcool. I use Havoline which is OEM fill.

If you have any questions just post them here. dloch, growe3, zonie77 and myself have all done this recently. And as you have noticed bbobynski, a GM engineer on the Northstar project, is usually checking in.

Good Luck

Lawrence
05-21-04, 02:26 AM
The guys that have pulled them out the top comment on how hard it is to get bolts out etc. Much easier to drop the cradle!
Really the only bolts that are difficult to remove are the exhaust manifold bolts, but they have to go whether it comes out the top or the bottom.

zonie77
05-21-04, 11:27 AM
Lawrence,
Yes, but they are sooooooooooo easy with the cradle out (LOL). :rolleyes:

zonie77
05-21-04, 11:43 AM
You do not have to disconnect the ABS when you drop the cradle. You can drop the cradle without discoing any brake lines.

I have the equipment to do AC so it was no big deal for me. Recharging AC isn't that hard and Harbor Freight now has gauge sets for $50 and the venturi style vacuum pump for $10 (when on sale). You can always resell and get most of your money back if you think you will never use again. Having the gauges is so much better than those refill kits. Those things are terrible. If you decide to recharge the ac I'll give you some info.

About the leak. I think you are right to clean it and decide how bad it is. You are right about not doing it twice. Luckily both of mine weren't leaking bad enough to reseal.

Lawrence has some good info. I recommend new gaskets too. For the little extra cost you don't get another leak when you finish. I know bbobynski sez to reuse but it just isn't worth taking a chance of an annnoying leak, either oil or intake.

eldorado1
05-21-04, 12:21 PM
eldorado1 made a mistake with regard to the "green coolant". Don't use it. Use only Dexcool. I use Havoline which is OEM fill.

Not to get off topic, but I've been hearing that Dexcool is the devil in orange clothing... Not just on this forum, but elsewhere too...

http://www.consumeraffairs.com/automotive/gm_dexcool.html

Lawrence
05-21-04, 01:19 PM
Not to get off topic, but I've been hearing that Dexcool is the devil in orange clothing... Not just on this forum, but elsewhere too...

http://www.consumeraffairs.com/automotive/gm_dexcool.html
Hmmm, I have never heard of any problems like that. I would still use Dexcool and maybe just change it more often.

bbobynski, any merit to those complaints?

zonie77
05-21-04, 01:57 PM
I have a 97 Blazer with Dexcool and havn't had these problems. If I start having problems I will switch to Green coolant in a flash.
Bbobynski gave some info about the Dexcool sludging when the system would get air in it. The sludge is actually rust. In a N* you don't have very much iron in contact with the antifreeze. The Blazer has iron block and heads.

It makes me wonder if some of the problem vehicles have a minor leak that isn't being addressed. One needed a water pump shortly after the initial flush and the first one is constantly smelling antifreeze. Maybe a heater core that needs replacement?

eldorado1
05-21-04, 02:15 PM
IMO, any time you have a new product released, there will always be little "issues" that come up... I'd rather just avoid them all together, and stick with the tried and true. Yes dexcool will last longer, and not eat away your waterpump seals, but I'm familiar with the green stuff. In the end, it gets the job done just as well... Just call me afraid of change :yawn:

BeelzeBob
05-21-04, 02:17 PM
A similar thread was covered in another forum. See the following link and my comments.

Basically, there is nothing at all wrong with DexCool. There are some issues with the way people use and mis-use it.....but it is an excellent product.



Saw this in a Chevy truck forum. Interesting. Maybe BobB has some information on this. Hope the link works.

http://www.chevytalk.org/threads/showflat....true#Post822038 (http://www.chevytalk.org/threads/showflat.php?Cat=&Board=UBB64&Number=822038&Forum=All_Forums&Words=&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=1day&Main=821882&Search=true#Post822038)



Sounds like someone who does not know what he is talking about that is quoting bits and pieces from different places in order to sound authoritative...... basically more BS in other words.

He obviously did not just "accidentally" confuse DexCool with propyleneglycol if you read his first post.....later tried to make it look that way when called on it....

DexCool is running satisfactorily in millions and millions and millions of cars and trucks....it is proving to be a very robust product in terms of very long life, excellent corrosion protection and is very "friendly" to water pump seals.

The silicates in the conventional green silicated coolants are naturally very abrasive. The more silicates added to the coolant the better the corrosion protection....BUT....the more aggressive the silicates are in tearing up water pump seals. That is what limits the silicate levels in conventional coolant and why DexCool is much easier on water pump seals....it has no silicates.

Both DexCool and the conventional green coolant are ethyleneglycol based. There is no advantage nor disadvantage in DexCool with regard to cooling, thermal conductivity, specific heat, viscosity or anything....???? Wonder where the reference to "better cooling" came from.

The issues with DexCool over the years are way overblown and typically due to mis-mixing the product, mixing with other products (non-DexCool compliant), running systems low on coolant, etc. I have NEVER seen any information concerning DexCool being harmful to a cooling system or not performing correctly when used correctly.

It is incorrect to say that Saturn used DexCool before Gm went across the board with it in 96..... The product that Saturn used was a partially silicated coolant that is somewhat similar to the product discussed that is being used in Europe. That product was used by Saturn for several years prior to the introduction of DexCool partially because they wanted a longer life product and DexCool was not validated yet. DexCool OUTPERFORMS that product which is why it was chosen for validation and implementation.

There is NOTHING that performs better than DexCool that I have seen in terms of corrosion protection. I would put it against anything. Having run aluminum head Northstar engines at well over 300 Hp for 400 hours and longer with no hot deposition corrosion nor any thermal cracking seen due to corrosion related stress risers I would defy any product to perform better for corrosion protection. That is one of the most stringent tests around for coolant corrosion protection levels and DexCool performs admirably.

DexCool "cools" the same as other ethyleneglycol coolants....because...it is an ethyleneglycol coolant and has the same viscosity, specific heat, etc.....

Propylene glycol , on the other hand, does NOT cool as well as ethyleneglycol due to the fact that it is more viscous and does not flow as well.

The "Evans" propylene-glycol story is basically a bunch of BS. Sounds good and he talks a GREAT line...but....it really doesn't pan out in practicality. Reverse cooling and PG is a great myth that some people are still trying to make a bundle on.


If the car/engine came with DexCool continue to use it. It it came with conventional green coolant, I would recommend continuing with the conventional green coolant. About the only advantage to changing to DexCool would be the elimination of the silicate contamination of the water pump seal....and if the system was already run with silicated coolant the water pump seal is already contaminated....so changing the pump also would be necessary for a fresh baseline on extending the water pump seal. As good as DexCool is for corrosion protection....the silicated coolant does just as good a job...as long as it is changed and refreshed occasionally....something the DexCool does not need.


DexCool causes perceived problems in some iron engines when they were run low on coolant. If the cooling systems are low, parts of the iron internal engine coolant passages dry out and rust. Then, as the coolant sloshes thru the engine, the rust washed off...and then the surface rusts again due to the heat rapidly drying it. The DexCool does NOT provide corrosion protection when it is not present...i.e..the passage is dry. All that rust getting washed into the coolant gradually clogs the system, unseats and clogs the radiator cap seals, etc...and the engine overheats.... Then the owner is horrified to find the system full of "rust". If they had kept the system full of coolant it would have been fine. Not the DexCool....low cooling sytsems.



BTW....I would expect a "Ford" engineer to dislike and talk DexCool down.... They had the chance to use the long life coolant and turned it down....so "of course" it is no good...not invented here , you know. Ford had a real problem testing DexCool with some of their radiators and heat exchangers coming apart... Not all aluminum alloys are compatible with DexCool...which is why it is not a good idea to self prescibe it's use in non-specified applications. The Ford radiators and heater cores were attacked by DexCool and they failed. something that GM knew about going in and changed the radiator construction long long ago to an aluminum alloy that was compatible. DexCool actually started development/testing back in the mid to late 80's so it has been around quite awhile.

Saturn had that little problem with heater cores failing in some cars years ago because they received a "premixed" batch of pre-DexCool coolant that was not "premixed"....duh....the supplier paid for that. Lots of cars affected due to the supplier not supplying the correct material to the assembly plant and quite a few cars were produced before it was caught. Once again, though, not the fault of DexCool or the pre-DexCool OAT coolant....a problem with the correct mix ratio.

dloch
05-21-04, 04:45 PM
I replaced my HVAC cover although the original didn't look bad.... but for the cost I wasn't going to take a chance. I also covered the lower section of it and the section of the floorpan where the exhaust makes the turn with dynamat extreme to reflect some of the heat.

I agree with lawrence about all the gaskets and seals. I changed everything except for the oil manifold. I didn't want to take the chance on any leaks.

Make sure you have a number of different length 15MM sockets and swivels. Another popular size is 10mm with a scattering of 13mm thrown in for good measure. Like Lawrence said get some extentions......

As far as coming out the top or removing the cradle.. it's up to you. I took mine out the top like Lawrence, when I do it again I will try dropping the cradle just for kicks. My reason for coming out the top was that I wanted a rolling chassis with the motor out. The other car in my garage is a non-roller.

There was only three or four bolts that were a major PITA to get back in. If get the right angle on them it isn't an issue.. make sure you clean the threads on the exhaust manifolds flanges where they connect the lead pipe from the convert to the exhaust manifold..... I would recommend new bolts there as well, mine were rusted...

Like Lawrence has said... be patience in either case, and just remember you aren't blazing new territory here, it has been done either way. Choose the method that makes you the most comfortable.

Good luck.

zonie77
05-22-04, 02:22 PM
Bobvondutch,
Thanks for the kind words earlier, sorry I didn't respond before. It's nice to know I'm of some help. One of the old board members gave me some help when I did the first one so I like to pass it on.