Cadillac Seville / Cadillac Eldorado Forum Discussion, northstar HG miracle ? in Past Cadillac Vehicle Discussion; Some time ago, I posted a threat about loosing coolant from my eldorado TC Northstar engine. At this time, I ...
Some time ago, I posted a threat about loosing coolant from my eldorado TC Northstar engine. At this time, I had also other symptoms of a head gasket problem : bubbles heard when engine just stopped after driving some hills (i live in Reunion, a mountainous island), rough start after a night rest, but no overheating.
Since then, I started the engine several time mainly to charge the battery and also have some driving with some WOTs on the roads close to my home (hills), and guess what ? No more HG symptoms : smooth engine, perfect iddle, no bubbles heard, no coolant smell.
Does someone has an explaination ?
Thanks for your ideas.
Do you think two much coolant in the reservoir could have involve a problem ? I think of this because I had the problem almost immediatly after servicing of the car.(in a garage).
I also followed the PROMAR break in instructions which were quite rough.
Do you think a clogged purge line could have involve the same symptoms than HG failure : bubbles, hard start next morning, irregular idle, smell of coolant in the cabin ?
I contacted PROMAR after the rebuilt engine has been installed to know how to break in correctly the engine. I had read on forums and technical infos that to avoid excessive oīl consumption and to make pistons ring gaskeks seat properly, a correct break in was needed.
Here is what was stated : 2nd gear 0 to 60 mph several times.
I didn't find the right place for this kind of driving so what I did is drive "normally" in 3rd gear and kick down to 2 nd and accelerate to 60 mph. I did it several times
and when back home and stopped the engine I heard bubbles. The next day the engine started roughly with bad idle. I drove the car and noticed again the bubbles when I stopped the engine. Coolant was also pouring from the overflow line of the reservoir, but very important I never had overheating. Temperature always below 225 ° F.
The carpet is not wet. The coolant smell I noticed came from the engine to the cabin, I guess ...
Automobile(s): 2002.5 F55 STS, 2014 Explorer XLT 4WD
MD Eastern Shore
Re: northstar HG miracle ?
Rebuilt engines need a breakin period. Your instructions were close to accepted practice.
You don't state the year of your engine, but ...........for professionally rebuilt automotive engines - the breakin is usually
For a flat-tappet cam you start the engine and immediately accelerate it to 1500 - 1800 rpm for a minimum of 15 minutes, then drive for an hour or two, never keeping rpm constant for more that 15-20 seconds - up and down. After 250 miles you can work the engine up to redline under light loads, increasing loads up until complete breakin at 500 miles or so. Then you change the oil and filter.
For a roller cam (2000 and later Northstar) the cam breakin is not used - drive the car normally with speed increases and decreases for the first 250 miles, then work it up to full rpm and power by 500. Change oil and filter.
For any engine, the way it was used for the first few hundred miles of life determines its ultimate reliability and life expectancy.