overheating problem after serp engine cam change - help!
Discussion
just fitted stealth cam to my 500 serp, refilled cooling system, started up and after the initial clatter of cam followers the engine sounds sweet. However the indicated temperature shot up and kept on climbing past 90C so shut down. tried numerous procedures described on the forum including bleeding the rad, rigging up a pipe and funnel to fit in to the header tank/swirl tank and much squeezing of hoses to expel air. All to no avail, the temperature still shoots up above 90 in just a minute of starting.
Am I missing something? the bottom hose from the water pump gets hot, both heater rail pipes got hot but the radiator top hose stays cold as does the header tank and hose to the thermostat .
I did wonder if it is possible to fit the valley gasket round the wrong way and thereby block off a waterway, if not it would seem that I have an airlock somewhere.
Any one else had this problem following a complete drain of the cooling system, advise would be much appreciated.
Am I missing something? the bottom hose from the water pump gets hot, both heater rail pipes got hot but the radiator top hose stays cold as does the header tank and hose to the thermostat .
I did wonder if it is possible to fit the valley gasket round the wrong way and thereby block off a waterway, if not it would seem that I have an airlock somewhere.
Any one else had this problem following a complete drain of the cooling system, advise would be much appreciated.
I take it you had a similar problem with a serpentine engine or is it just me?
I thought that maybe my makeshift pipe and funnel arrangement having a head of water 18" above the header combined with squeezing the flexible hoses would have forced out the air. However I'll give your solution a go, can you confirm you did mean to say into the thermostat housing rather than the water pump. Unfortunately I'm away now until tuesday week, will get wify to source some suitable piping and have a go when I return.
Thanks Quinny
I thought that maybe my makeshift pipe and funnel arrangement having a head of water 18" above the header combined with squeezing the flexible hoses would have forced out the air. However I'll give your solution a go, can you confirm you did mean to say into the thermostat housing rather than the water pump. Unfortunately I'm away now until tuesday week, will get wify to source some suitable piping and have a go when I return.
Thanks Quinny
Looks to me from the photo that you can't really get the valley gasket round the wrong way.
A good call TVR Beaver, I haven't bled from the small short pipe with the bolt in the end of it, I assume there could be an air lock.
I'll go for the stat next. I'm away for the next week so will give it a go when i return home.
Thanks all for your responses, I will post again hopefully with good news.
A good call TVR Beaver, I haven't bled from the small short pipe with the bolt in the end of it, I assume there could be an air lock.
I'll go for the stat next. I'm away for the next week so will give it a go when i return home.
Thanks all for your responses, I will post again hopefully with good news.
yes I can hear the ball in the stat, Not sure about hole in the stat, need to remove housing.
Probably wrong with the timing, maybe my perception and panic! although I'm sure it wasn't much more than a couple of minutes from cold to passing 90C on the gauge.
I'll have another go bleeding the system at the weekend and provide an update.
Thanks to all for the input
Probably wrong with the timing, maybe my perception and panic! although I'm sure it wasn't much more than a couple of minutes from cold to passing 90C on the gauge.
I'll have another go bleeding the system at the weekend and provide an update.
Thanks to all for the input
yes I can hear the ball in the stat, Not sure about hole in the stat, need to remove housing.
Probably wrong with the timing, maybe my perception and panic! although I'm sure it wasn't much more than a couple of minutes from cold to passing 90C on the gauge.
I'll have another go bleeding the system at the weekend and provide an update.
Thanks to all for the input
Probably wrong with the timing, maybe my perception and panic! although I'm sure it wasn't much more than a couple of minutes from cold to passing 90C on the gauge.
I'll have another go bleeding the system at the weekend and provide an update.
Thanks to all for the input
The continuing saga:
serp belt routing OK, bled the short pipe on the left hand side of the inlet manifold - no air
so decided to check the thermostat which opened with boiling water
re fitted thermostat housing without the thermostat fitted
topped up system and completed ritual squeezing of pipes until no bubbles observed from my makeshift reservoir on copper pipe fitted to the header tank
started engine, engine temperature increased slower than previous attempts, after 3 0r 4 mins when approaching 90C I turned off engine, removed reservoir and pipe and fitted brass screw in header tank
restarted engine, temperature increased and I chickened out and turned off engine as temperature just passed 100C
Much scratching of head and remembered that I had snipped off the manky knackered last 4 inches of the single wire and insulation sleeve going to the temp sensor (fitted on top of the inlet manifold) and soldered a new 4 inch length of wire and connector.
So, I'm now wondering whether I have an indication problem rather than an overheating problem.
The question: should the wire to the temp sensor have an in line resistor and have I inadvertently removed it along with the manky section of wire?
Apologies for war and peace
serp belt routing OK, bled the short pipe on the left hand side of the inlet manifold - no air
so decided to check the thermostat which opened with boiling water
re fitted thermostat housing without the thermostat fitted
topped up system and completed ritual squeezing of pipes until no bubbles observed from my makeshift reservoir on copper pipe fitted to the header tank
started engine, engine temperature increased slower than previous attempts, after 3 0r 4 mins when approaching 90C I turned off engine, removed reservoir and pipe and fitted brass screw in header tank
restarted engine, temperature increased and I chickened out and turned off engine as temperature just passed 100C
Much scratching of head and remembered that I had snipped off the manky knackered last 4 inches of the single wire and insulation sleeve going to the temp sensor (fitted on top of the inlet manifold) and soldered a new 4 inch length of wire and connector.
So, I'm now wondering whether I have an indication problem rather than an overheating problem.
The question: should the wire to the temp sensor have an in line resistor and have I inadvertently removed it along with the manky section of wire?
Apologies for war and peace
Thanks for the photos Ronald. I am absolutely positive my temp lead was connected by bullet connector to the 'unused' connector and not the one on the front face of the inlet manifold.
I'm now wondering whether the sensor on the front of the inlet manifold was found faulty in the past and rather than change it someone previously connected the wire to the 'unused'sensor as it was easier to access. I'm going to add a fly lead with spade connector to the temp lead and attach it to front of manifold connector and see if it works, I've also purchased a Maplin infrared thermometer to try and monitor the real temperature.
I also wondered if the original lead had a resistor in it (as mentioned previously) to compensate for less resistance of the unused sensor thereby giving a acceptable 90C gauge reading when engine has warmed up.
Do pre seeps use the 'unused' sensor with a resistor in the lead?
The saga continues but not until the weekend now.
I'm now wondering whether the sensor on the front of the inlet manifold was found faulty in the past and rather than change it someone previously connected the wire to the 'unused'sensor as it was easier to access. I'm going to add a fly lead with spade connector to the temp lead and attach it to front of manifold connector and see if it works, I've also purchased a Maplin infrared thermometer to try and monitor the real temperature.
I also wondered if the original lead had a resistor in it (as mentioned previously) to compensate for less resistance of the unused sensor thereby giving a acceptable 90C gauge reading when engine has warmed up.
Do pre seeps use the 'unused' sensor with a resistor in the lead?
The saga continues but not until the weekend now.
Hallelujah, problem fixed!
A previous owner had connected to the rover temp sensor (usually unused on a serp) on top of manifold next to the ecu temp connector rather than the one on the front of the manifold behind the distributor.
As I suspected when I snipped off the manky knackered last 4 inches of the wire and insulation I also unwittingly removed the resistor with it.
I then spliced/soldered in a new wire tail and connector minus resistor, resulting in a worrying but false gauge reading going into 100C+.
So the solution was to connect a 160 ohm resistor from Maplins (didn't have a 170 ohm one as suggested on forum post) in the wire, this resulted in a gauge indicated running temperature of 82C. Checked temps around the engine with an infrared temp gun all over the cooling system, in particular at the hose connected to the bottom of the header tank, this gave a reading of 89C. At last, problem resolved although I will try a 170 ohm or maybe a variable resistor to tweak up the normal engine running gauge indicated temp to 90C.
Finally, I would like to thank everyone who contributed to this thread and to say what a great forum this is. Along with bringing to my attention TVR's little resistor trick (the bu@@ers!), I also received some great advice on bleeding the cooling system.
Looking forward to a long run out tomorrow to try out the stealth cam http://www.pistonheads.com/gassing/imgs/2.gif
Thanks again guys
A previous owner had connected to the rover temp sensor (usually unused on a serp) on top of manifold next to the ecu temp connector rather than the one on the front of the manifold behind the distributor.
As I suspected when I snipped off the manky knackered last 4 inches of the wire and insulation I also unwittingly removed the resistor with it.
I then spliced/soldered in a new wire tail and connector minus resistor, resulting in a worrying but false gauge reading going into 100C+.
So the solution was to connect a 160 ohm resistor from Maplins (didn't have a 170 ohm one as suggested on forum post) in the wire, this resulted in a gauge indicated running temperature of 82C. Checked temps around the engine with an infrared temp gun all over the cooling system, in particular at the hose connected to the bottom of the header tank, this gave a reading of 89C. At last, problem resolved although I will try a 170 ohm or maybe a variable resistor to tweak up the normal engine running gauge indicated temp to 90C.
Finally, I would like to thank everyone who contributed to this thread and to say what a great forum this is. Along with bringing to my attention TVR's little resistor trick (the bu@@ers!), I also received some great advice on bleeding the cooling system.
Looking forward to a long run out tomorrow to try out the stealth cam http://www.pistonheads.com/gassing/imgs/2.gif
Thanks again guys
No problems Pete, you were very close but at the time of your valued response I wasn't aware of the significance of the sensor switch from TVR to Rover and the associated resistance difference. Thanks anyway, I've quite enjoyed this 'journey' of learning in a masochistic way! TVRs don't you just love 'em.
No problems Pete, you were very close but at the time of your valued response I wasn't aware of the significance of the sensor switch from TVR to Rover and the associated resistance difference. Thanks anyway, I've quite enjoyed this 'journey' of learning in a masochistic way! TVRs don't you just love 'em.
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