Bad news kids....

Bad news kids... it's terminal. Took my 95 3/4 ton 4X4 6.5 diesel suburban in complaining of temp gauge going high and dropping, alternator... ball joint fears.... And I just got a call, it's got a cracked head. So this is how it ends. Husband aint never gonna fix it. I knew this day was coming. He said the temp gauge going high then dropping is some sort of coolant preasure build up and release. I seen it every morning for the last year. He said he took her up to 120 kms and it did exactly what I said. And he knows exactly what my problem is. It's true, Toni knows this truck. So any guesses how long I got? What will happen when it goes? When would you park it for good? My last over heat was a couple years ago when a belt blew off, big heat is the only thing that would have cracked a head right? So the crack might be that old. And it's sad news. Drivin it since birth, 95. What would you guys do with it?

depends on how much you like the truck. call around and see how much replaceing the head will cost. if you were in the states i would say buy a ex milltray truck and swap motors. being a diesel i would do a search and see if just replaceing the head is worth it.

Thanks Gremlin.... interesting... I didnt know the US Millitary used Chev Suburbans. I do know that my suburban (and it's always Navy) shows up all over old American T.V. and movies. I have 3 kids and they spot it everytime, it's definately had it's glory days. I watched an American show once where they armored my sub and added a huge machine gun on top. I'm not sure why. Michael Jackson had one also, even seen it on amimal cops. Here Dutch women with 7 kids drive em and the police and thats where they've been popular since the 90's. I love it, been driving it for 15 years, it feels like home. I rarely put it into 4 wheel drive, never spun the tires, really babied it and cant believe it could turn on me like this. It does have 383 000 kms on it, but after one rebuild (heads) didnt that add life to it?

Now I came back because I have a problem... A friend said get a second opinion. The first mechanic diagniosed it with a cracked head... because the heat guage has a habit of rising 20 degrees or so and dropping quickly. This always happens in the first 5 miles after it has sat over night, and at times during my driving day. He said it was a build up of preasure in my coolant system and a release which meant it had a cracked head. The second mechanic asked..have you lost power - no. Loose coolant - no. Over heated it - no. Use oil - slightly. Then he did a chem test where if there if some thing shows up in my rad that the dye changes color. Thats all I know about this test. Well he called me yesterday and said there isnt a thing wrong with my engine and he ordered a thermostate. So I'm going to get it back today apparently fixed. So how should my tempurature gauge operate? Should it come up to 90 and stay there. Does it move around according to how hard I'm pushing it. Should it rise up from say from a hill or some kind of highway climb? If there is a range, how far can it swing if all is running normally? I dont know what to think now. The first mechanic knows that truck and has had his hands all over the 6.5s since they came out. Could it be he can detect a cracked before it is noticable on this dye test?

Thanks Gremlin.... interesting... I didnt know the US Millitary used Chev Suburbans. I do know that my suburban (and it's always Navy) shows up all over old American T.V. and movies. I have 3 kids and they spot it everytime, it's definately had it's glory days. I watched an American show once where they armored my sub and added a huge machine gun on top. I'm not sure why. Michael Jackson had one also, even seen it on amimal cops. Here Dutch women with 7 kids drive em and the police and thats where they've been popular since the 90's. I love it, been driving it for 15 years, it feels like home. I rarely put it into 4 wheel drive, never spun the tires, really babied it and cant believe it could turn on me like this. It does have 383 000 kms on it, but after one rebuild (heads) didnt that add life to it?

Now I came back because I have a problem... A friend said get a second opinion. The first mechanic diagniosed it with a cracked head... because the heat guage has a habit of rising 20 degrees or so and dropping quickly. This always happens in the first 5 miles after it has sat over night, and at times during my driving day. He said it was a build up of preasure in my coolant system and a release which meant it had a cracked head. The second mechanic asked..have you lost power - no. Loose coolant - no. Over heated it - no. Use oil - slightly. Then he did a chem test where if there if some thing shows up in my rad that the dye changes color. Thats all I know about this test. Well he called me yesterday and said there isnt a thing wrong with my engine and he ordered a thermostate. So I'm going to get it back today apparently fixed. So how should my tempurature gauge operate? Should it come up to 90 and stay there. Does it move around according to how hard I'm pushing it. Should it rise up from say from a hill or some kind of highway climb? If there is a range, how far can it swing if all is running normally? I dont know what to think now. The first mechanic knows that truck and has had his hands all over the 6.5s since they came out. Could it be he can detect a cracked before it is noticable on this dye test?

the engine temp should rise slowly on a cold start. climb until at the normal temp ..about 190 deg f. or whatever that is in C ..92 ?

then is should not change if the coolant system is good and operating correctly. cracked head will cause the engine to run bad..water in oil and out the exhaust and even damage the starter if the cylinder has coolant in it. dye will and is used to detect leaks..

thermostats are good for 4 years or so...sometimes defective out of the box ! I would also replace the coolant radiator pressure cap...use the same or slightly lower pressure than the OEM ...if its 15 psi then you use 15 psi or lower..never use a 16 psi in the 15 psi coolant system...

So the thermostat is taking an extra day or two to come in, supposed to be here tomorrow. He thinks it is the problem. He said he's even gonna test it. He did do the dye test also, and said it does not have a cracked head. Said there were no bubbles either which apparently is a good thing. Says it runs great... now this is where I start loosing confidence. It a bloody 17 year old truck, lets not get too excited cuz I'm sure there is always something on the brink. He said also that I had 2 inches too much coolant in it and the antifreeze was way high. Does this matter? That first mechanic did mention the rad cap also. He said I have a 16 lb (it came on it) but could replace it with something smaller. Didnt tell me from where or anything more. So where would I get such a thing?

First I'm told it's finished, now that it needs some small part and runs perfectly.... I dont know what to think. After picking it up tomorrow I will definitely watch to see if it rises up from cold and can hold at 90. I dont think I've ever seen it able to do that in years, and it not only would it go over buy 10 or 20, it sometimes got way cool. Can thermostats stick open and closed? Fingers crossed, will let you know how it turns out.

So the thermostat is taking an extra day or two to come in, supposed to be here tomorrow. He thinks it is the problem. He said he's even gonna test it. He did do the dye test also, and said it does not have a cracked head. Said there were no bubbles either which apparently is a good thing. Says it runs great... now this is where I start loosing confidence. It a bloody 17 year old truck, lets not get too excited cuz I'm sure there is always something on the brink. He said also that I had 2 inches too much coolant in it and the antifreeze was way high. Does this matter? That first mechanic did mention the rad cap also. He said I have a 16 lb (it came on it) but could replace it with something smaller. Didnt tell me from where or anything more. So where would I get such a thing?

First I'm told it's finished, now that it needs some small part and runs perfectly.... I dont know what to think. After picking it up tomorrow I will definitely watch to see if it rises up from cold and can hold at 90. I dont think I've ever seen it able to do that in years, and it not only would it go over buy 10 or 20, it sometimes got way cool. Can thermostats stick open and closed? Fingers crossed, will let you know how it turns out.

T-stats can and do stick in either position, but the "too much coolant" makes me think leaking head gasket or similar because it would push coolant back into the system against its normal path. Of course, a bad head gasket is not worth throwing the truck away. Cracked head....different matter (unless you have access to cheap/free labor).

Well I know why there is too much coolant in her...husband did it. Over does everything, thats how the extra antifreeze got in there too. But head gasket sounds right, no $80 part is gonna fix that truck, I just cant see it. Today is the day...

Well I know why there is too much coolant in her...husband did it. Over does everything, thats how the extra antifreeze got in there too. But head gasket sounds right, no $80 part is gonna fix that truck, I just cant see it. Today is the day...


your problem of temp variation is a good possibility the themostat is the cause. max coolant to distilled water is 75%..If you have too high a coolant ratio 90% to 10% water when the temp drops to 40below zero F the coolant will turn to slush and the temp will not be correct ..damage can occur.. if you live in this very cold area 70% is what I would use. get a test kit to ensure you have the correct coolant to water ratio..

if the coolant level is too high it will just leak out the overflow..

thermostats stick open or closed..open is best no damage..closed will damage the engine...not operating at the correct temp over time will damage the engine and cost you on excess fuel...


replace the thermostat with a 15 psi...I have never seen a GM vehicle of this type with 16psi pressure cap...aftermarket type is what you have ...I doubt it is a GM cap...

if 15 psi is not available use 14.5 psi etc...or purchase on line/internet..

Well at least I got a call. He replaced the thermostat and says 20 or 120 km, doesnt matter it holds at around 95 give or take a needle width. I dont recall the last time that gauge wasnt swinging up and down as I drove, at least a year, I'm sure more. So I dig in the desk, as far as I can see it hasnt had a thermostat since we replaced the heads... 7 years ago. But he wanted to keep it over night again and run another dye test to be sure. Also said he wants to see what the aternator gauge is doing bouncing around, it always does. Otherwise he said it drives great, he'd drive it to Vancouver (12 hours). Well now, I dont know about that, I like to stay within my roadside max distance free tow radius. Almost excited to see how she goes tomorrow. Used to be a truck I could take anywhere anytime no matter the weather or conditions. A snow drift bringing you to a complete hault just ment you had to back up and hit it again. Lately I'd only drive it during the day, when it was warm out but not too warm and never fuether than 40 kms.

Used to be a truck I could take anywhere anytime no matter the weather or conditions. A snow drift bringing you to a complete hault just ment you had to back up and hit it again. Lately I'd only drive it during the day, when it was warm out but not too warm and never fuether than 40 kms.

:) Which is why I hang onto my '96, even though I bought a replacement (2005) for it last year. They are just plain tough trucks that I feel I can trust to go anywhere. The '05....not so much.

Well at least I got a call. He replaced the thermostat and says 20 or 120 km, doesnt matter it holds at around 95 give or take a needle width. I dont recall the last time that gauge wasnt swinging up and down as I drove, at least a year, I'm sure more. So I dig in the desk, as far as I can see it hasnt had a thermostat since we replaced the heads... 7 years ago. But he wanted to keep it over night again and run another dye test to be sure. Also said he wants to see what the aternator gauge is doing bouncing around, it always does. Otherwise he said it drives great, he'd drive it to Vancouver (12 hours). Well now, I dont know about that, I like to stay within my roadside max distance free tow radius. Almost excited to see how she goes tomorrow. Used to be a truck I could take anywhere anytime no matter the weather or conditions. A snow drift bringing you to a complete hault just ment you had to back up and hit it again. Lately I'd only drive it during the day, when it was warm out but not too warm and never fuether than 40 kms.

what you need is a log book that has the repairs,dates, and mileage recorded. coolant with now the newer long life coolants you can go about 3-4yrs with normal mileage and distilled water. the thermostat should be replaced at this time. only use distilled water. flush the heater core to ensure you get max heater operation..

understanding the owners manual on the maintenance required and using these forums will guide you to keeping your vehicles in good running condition a long time.

the new GM vehicles are not made as durable as your 1996. issues with the engine and transmissions is becoming a big problem..

the new vehicles look great...but the owners are very unhappy with performance. keep up the required maintenace and with proper care you will be surprised how long it will run good..

I had a vehicle 17 yrs 380,ooomi. ran great no major repairs ...reason I sold it was rust on the frame/body mounts..still passed emissions test and used 1/2qt of oil at the 3500 mi oil change..

only one time it died on me. starter solenoid failed at 225,ooomi.

I'm in shock! He's got the whole truck running perfect. He put in a chev thermostat and said the last one was Napa auto, said to never do that again. I'm so used to it trying to over heat everywhere I went, not so now... if anything she runs cool. I raced up the hill, 120 km on the highway, no rise. Like I said, runs cool if anything. Woot! Second dye test done, he said absolutely no cracked head, gaskets are good. The altenator gauge turns out is a bit screwed, drops down now and then, but he said it's the gauge, altenator is working perfectly. The clunk I was hearing (feeling) was a loose bolt, on the stuff that attaches one of the front tires, ball joints were good, everything there good, tightened the bolt, yup thats gone. BUUUUT... What the hell is that sticking up hose on the right of the rad. I think I was told it was an over flow. Like a sticking up hose with a special tip on it. It was dripping when I first got it back today, went to town, it seems to have subsided. Wonder if that is because it's been pushed a little more than usual today.

Going to have to get used to the way it runs now, I guess again. That thermostat had been screwed for a long time (year or two), I got accustomed to driving to how the truck was reacting. It was different everyday. Kinda strange with all that gone now. A log would help a mechanic, just a binder of all my reciepts in order would answer the questions he had to phone repeatedly about. And if all goes well for a while, I think I will regain confidence in her, no fear right guys? She's the best of the last.

PS: almost for got the best part. Three days of tightening, fixing, checking and rechecking plus 1 new thermostat.... $180!

PS: almost for got the best part. Three days of tightening, fixing, checking and rechecking plus 1 new thermostat.... $180!


thanks for the report on your repair.

the lesson you learned is the person repairing your vehicle in the past should be avoided. having a repair tech familiar with your vehicle is very important especially when they get this old.

with the coolant level too high it will come out of the overflow hose ..I would suck some out..

thermostats are specific to the vehicle . a NAPA part used in your vehicle was most likely the wrong one. also thermostats made today have very poor quality. testing the part before install can save alot of time if the test reveals its defective. most reliable thermostats have a warrantee .

with a log book on vehicle repairs this aids "you" ...this will reveal what was done and if your up to it what needs to be done as the time/mileage increases..also having a record of repairs and service improves your chances of a quick sale when that time comes.


good luck

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