1999 2.5 boxster rough idle, running hotter on one bank
12-28-2017, 02:56 PM
#1
1st Gear
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1999 2.5 boxster rough idle, running hotter on one bank
Bought a second hand 2.5 boxster engine with suspect head gasket, used the bottom end of this engine (as mine has scored bores) and the heads off my original engine.
When you start the engine up it is running rough at idle and is also running much hotter (50f) difference on the left hand bank 4,5 &6
I have checked the timing replaced the plugs & coil packs, compression is 195psi on both banks
No air leaks
Not sure where to go nxt
When you start the engine up it is running rough at idle and is also running much hotter (50f) difference on the left hand bank 4,5 &6
I have checked the timing replaced the plugs & coil packs, compression is 195psi on both banks
No air leaks
Not sure where to go nxt
12-30-2017, 02:46 PM
#2
Race Director
Bought a second hand 2.5 boxster engine with suspect head gasket, used the bottom end of this engine (as mine has scored bores) and the heads off my original engine.
When you start the engine up it is running rough at idle and is also running much hotter (50f) difference on the left hand bank 4,5 &6
I have checked the timing replaced the plugs & coil packs, compression is 195psi on both banks
No air leaks
Not sure where to go nxt
When you start the engine up it is running rough at idle and is also running much hotter (50f) difference on the left hand bank 4,5 &6
I have checked the timing replaced the plugs & coil packs, compression is 195psi on both banks
No air leaks
Not sure where to go nxt
Even if dark are there any pending codes?
That big of temperature difference certainly suggests there is a coolant supply problem to the hot(er) bank.
Don't know if it is possible but you sure you have the coolant hoses routed correctly? You are not feeding hot coolant from one bank to the other bank? You are at the engine so you will have to approach this with the mindset there is a hose routing problem and trace each hose until you are 100% satisfied it is connected properly.
You sure the coolant hoses and passages to the hot bank are clear of any obstruction?
A rough idle from initial start though does suggest something besides a hot bank problem. The 2nd problem may or may not be responsible for the hot bank. Are you 100% positively absolutely sure the cam timing is correct?
There is another possible explanation. You installed the wrong head gasket on the hot bank or you installed the right head gasket wrong.
12-30-2017, 05:26 PM
#3
Rennlist Member
CEL dark? If not what are the codes?
Even if dark are there any pending codes?
That big of temperature difference certainly suggests there is a coolant supply problem to the hot(er) bank.
Don't know if it is possible but you sure you have the coolant hoses routed correctly? You are not feeding hot coolant from one bank to the other bank? You are at the engine so you will have to approach this with the mindset there is a hose routing problem and trace each hose until you are 100% satisfied it is connected properly.
You sure the coolant hoses and passages to the hot bank are clear of any obstruction?
A rough idle from initial start though does suggest something besides a hot bank problem. The 2nd problem may or may not be responsible for the hot bank. Are you 100% positively absolutely sure the cam timing is correct?
There is another possible explanation. You installed the wrong head gasket on the hot bank or you installed the right head gasket wrong.
Even if dark are there any pending codes?
That big of temperature difference certainly suggests there is a coolant supply problem to the hot(er) bank.
Don't know if it is possible but you sure you have the coolant hoses routed correctly? You are not feeding hot coolant from one bank to the other bank? You are at the engine so you will have to approach this with the mindset there is a hose routing problem and trace each hose until you are 100% satisfied it is connected properly.
You sure the coolant hoses and passages to the hot bank are clear of any obstruction?
A rough idle from initial start though does suggest something besides a hot bank problem. The 2nd problem may or may not be responsible for the hot bank. Are you 100% positively absolutely sure the cam timing is correct?
There is another possible explanation. You installed the wrong head gasket on the hot bank or you installed the right head gasket wrong.
12-31-2017, 02:26 PM
#4
Race Director
http://www.autoatlanta.com/porsche-p...section=103-00
12-31-2017, 05:21 PM
#5
Rennlist Member
If interchangable side to side why two different part numbers?
http://www.autoatlanta.com/porsche-p...section=103-00
http://www.autoatlanta.com/porsche-p...section=103-00
12-31-2017, 07:09 PM
#6
Race Director
Not trying to diagnose why the 1st engine failed. Just trying to come up with a possible explanation for the hot bank. If (granted, if) the wrong gasket used or it was installed incorrectly one or more coolant passages might be blocked off.
Doesn't have a to be a head gasket.
Not knowing in detail all the history of the heads it could be possible a water pump shed impeller vanes and the debris is blocking coolant flow through the head at critical points.
01-02-2018, 02:15 AM
#7
Rennlist Member
The head gaskets are different from bank 1 to bank 2. (coolant ports are sized different for optimum coolant flow)
Byprodriver you are correct in that the bank 1 and bank 2 head castings are the same, but they are not interchangeable due to machining of the oil passages and threading for the timing chain tensioners ect.
Byprodriver you are correct in that the bank 1 and bank 2 head castings are the same, but they are not interchangeable due to machining of the oil passages and threading for the timing chain tensioners ect.
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01-05-2018, 10:00 PM
#8
Rennlist Member
The head gaskets are different from bank 1 to bank 2. (coolant ports are sized different for optimum coolant flow)
It's been a long time since I installed a head so i forgot that point.
Byprodriver you are correct in that the bank 1 and bank 2 head castings are the same, but they are not interchangeable due to machining of the oil passages and threading for the timing chain tensioners ect.
It's been a long time since I installed a head so i forgot that point.
Byprodriver you are correct in that the bank 1 and bank 2 head castings are the same, but they are not interchangeable due to machining of the oil passages and threading for the timing chain tensioners ect.
01-06-2018, 03:46 PM
#10
Rennlist Member
2003 is the year head gaskets became interchangable for Boxster engines.