XK8 Timing-replacement
#1
03-02-2017, 07:17 AM
Join Date: Jan 2015
Location: Denmark
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XK8 Timing-replacement
Hey guys !
Im seeking guidance regarding my precious baby.
I've have recently changed the timingchain due to the left side exhaust crank had jumped 2 teeths. Before the procedure, the car had problems with running all cylinders. it would be overheating when the coolingsystem where closed. I was able to run idle, with the lid open. Had a pressure test, but the headgaskets are fine.
After assembly the car jumped into life and ran all 8. I took it for a spin and as it hit working tempature, it would cut off cyl: 1-4
The engine, even though running only right 5-8 cylinders has a steady spin in idle, and runs rpms without doubt.
As I drove the car home, on 4 cylinders, it would start both fans, and soon jump up in temp. I would then stop the car, wait untill the fan would stop and restart the car. The car would not start untill I had to remotely lock the car and open numerous times (Startjammer fault)
When it would run in cold weather. Left-side exhaust would pump out unburned fuel. Left side exhaust would run perfectly clear combustion.
So.
I read numerous blogs about potential faults.
Overheat:
Could my waterpump be broke, and if ? Is there a way to check, without draining the fluid?
Or, could the system contain airholes? Which way would be most efficient to clear?
Do the ECU enter a failsafe mode when opperating temp is reached ?
Are my coils fried?
Help me to revive my babe.
Hoping to hear some experttips
Im seeking guidance regarding my precious baby.
I've have recently changed the timingchain due to the left side exhaust crank had jumped 2 teeths. Before the procedure, the car had problems with running all cylinders. it would be overheating when the coolingsystem where closed. I was able to run idle, with the lid open. Had a pressure test, but the headgaskets are fine.
After assembly the car jumped into life and ran all 8. I took it for a spin and as it hit working tempature, it would cut off cyl: 1-4
The engine, even though running only right 5-8 cylinders has a steady spin in idle, and runs rpms without doubt.
As I drove the car home, on 4 cylinders, it would start both fans, and soon jump up in temp. I would then stop the car, wait untill the fan would stop and restart the car. The car would not start untill I had to remotely lock the car and open numerous times (Startjammer fault)
When it would run in cold weather. Left-side exhaust would pump out unburned fuel. Left side exhaust would run perfectly clear combustion.
So.
I read numerous blogs about potential faults.
Overheat:
Could my waterpump be broke, and if ? Is there a way to check, without draining the fluid?
Or, could the system contain airholes? Which way would be most efficient to clear?
Do the ECU enter a failsafe mode when opperating temp is reached ?
Are my coils fried?
Help me to revive my babe.
Hoping to hear some experttips
#2
03-02-2017, 08:45 AM
Veteran Member
Welcome to the forum. We need to remove some of the confusion from your post. Cyl. 1-4 are probably on the right when sitting in the car, and that is A bank. But that depends on the year , which you don't mention.
If you are dumping raw fuel out the left exhaust, you could damage the catalysts. Having skipped two teeth I would be concerned that there are bent exhaust valves, so a compression/leakdown test should be performed.
The plastic water pump vanes may be broken or the thermostat may be stuck closed. It would be a good idea to replace both. It's hard to determine the condition of the pump without removing it.
If you are dumping raw fuel out the left exhaust, you could damage the catalysts. Having skipped two teeth I would be concerned that there are bent exhaust valves, so a compression/leakdown test should be performed.
The plastic water pump vanes may be broken or the thermostat may be stuck closed. It would be a good idea to replace both. It's hard to determine the condition of the pump without removing it.
#3
03-06-2017, 06:34 AM
Join Date: Jan 2015
Location: Denmark
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#4
03-06-2017, 07:56 AM
2nd that:
Known issues where plastic impeller in waterpump, if unknown replacement be a great first suspect.
Cooling is basically an independent system, with a temperature sensor being read to feed info to the car current temp. Could internal engine parts causing issues, yes but you are not describing those symptoms.
If overheating there is only a few things to check.
system is correctly full of coolant
thermostat is opening as indicated by main hose getting hot and increasing a little in pressure
physically check upper and lower hose when engine is cool to be sure they feel evenly solid as you give them a light squeeze, you are checking to see if you feel signs of failing on the inside walls of hose
Past this it gets down to doing physical inspection by removing water pump and thermostat, only new gaskets required to reassemble if you think things are still functional, you can test thermostat out of car.
However if I was having cooling issues and had the pump off I would most likely replace it if I thought it was more than 5 years old, and a fresh thermostat is a low price item. Something to consider if you have the original crossover tube is do a replacement on that which will include a new temperature sensor, they are a type of plastic and can crack and leak. Complete replacement parts so far would be about $200 and when purchasing these parts they come with all the gaskets needed.
The other thing to check is radiator flow test to be sure it is not getting stopped up, from someone using tap water in the past to treat a leak. Done by draining coolant, remove lower hose refilling with water while bottom outlet covered, when uncovered the water should be coming out at high volume.
The upper and lower hoses should be changed if old as they are not that expensive and all eventually fail, and certainly 98 would be past due.
Sourcing parts online should be under $300 so far you will have found something that is causing the issue.
Not sure what year they changed it but early there was also a plastic thermostat riser that most would also suggest changing as a weak point that caused leaks and should be upgraded to metal.
Known issues where plastic impeller in waterpump, if unknown replacement be a great first suspect.
Cooling is basically an independent system, with a temperature sensor being read to feed info to the car current temp. Could internal engine parts causing issues, yes but you are not describing those symptoms.
If overheating there is only a few things to check.
system is correctly full of coolant
thermostat is opening as indicated by main hose getting hot and increasing a little in pressure
physically check upper and lower hose when engine is cool to be sure they feel evenly solid as you give them a light squeeze, you are checking to see if you feel signs of failing on the inside walls of hose
Past this it gets down to doing physical inspection by removing water pump and thermostat, only new gaskets required to reassemble if you think things are still functional, you can test thermostat out of car.
However if I was having cooling issues and had the pump off I would most likely replace it if I thought it was more than 5 years old, and a fresh thermostat is a low price item. Something to consider if you have the original crossover tube is do a replacement on that which will include a new temperature sensor, they are a type of plastic and can crack and leak. Complete replacement parts so far would be about $200 and when purchasing these parts they come with all the gaskets needed.
The other thing to check is radiator flow test to be sure it is not getting stopped up, from someone using tap water in the past to treat a leak. Done by draining coolant, remove lower hose refilling with water while bottom outlet covered, when uncovered the water should be coming out at high volume.
The upper and lower hoses should be changed if old as they are not that expensive and all eventually fail, and certainly 98 would be past due.
Sourcing parts online should be under $300 so far you will have found something that is causing the issue.
Not sure what year they changed it but early there was also a plastic thermostat riser that most would also suggest changing as a weak point that caused leaks and should be upgraded to metal.