|
Post by shaggydog007 on May 18, 2015 20:54:15 GMT 1
Hi All,
I'm new to forum and really hope somebody can help me with my ongoing problem.
Symptoms; ------------- expansion tank over pressurising air in coolant or possibly boiling car is fine and then suddenly overheats when under load or say for example going up hill - suggests air in system?
Work done so far to try and rectify ------------------------------ new header tank & cap new radiator new water pump new thermostat fully bled coolant sniff test = negative coolant system test to 20psi = holding pressure
Could it be a faulty EGR putting heat into coolant? Any other suggestions? I'm pretty desperate about it all to get it fixed as need my car daily.
Thanks for any advice!!!
|
|
|
Post by Karl on May 18, 2015 21:05:39 GMT 1
Hello shaggydog007
What's the year/mileage ?
Do the fans come on at correct speeds/frequency
Maybe worth carrying out a cylinder leak down test
Does it use any coolant or oil
Where did the new parts come from ?
|
|
|
Post by shaggydog007 on May 18, 2015 21:12:36 GMT 1
hi Karl
2008/65k
fan kicks in fine cylinder leak down test - agreed good idea I need to do that
only uses coolant if it over pressurises and throws some out no oil emulsification all oem Vauxhall parts altho vehicle is modified
|
|
|
Post by Karl on May 18, 2015 21:39:12 GMT 1
So if it's driven gently it's ok ?
What is it like in traffic ?
What modifications ?
|
|
|
Post by chippie on May 18, 2015 21:44:15 GMT 1
When the coolant pressure test was done, was this with the engine static or running?
I'm thinking head gasket.....leak down test with a hot engine if possible
|
|
|
Post by Rhubarb on May 18, 2015 22:34:01 GMT 1
Water pump lacking
|
|
|
Post by chippie on May 18, 2015 22:53:13 GMT 1
Water pump lacking Well the only other thing I can think of is a partial blockage...... No HC detected in coolant New pump New stat New rad New cap No air Press test ok
|
|
|
Post by valhalla on May 19, 2015 0:31:35 GMT 1
Hi there, When did the symptoms start to occur? After a lay-up in the garage, or a session of work on the car? A partial blockage, or a partial bypassing of the radiator, seems the most likely answer. What's the airflow like over the radiator, and is it much different to a "standard" VXR when it left the factory? Are all the air-seals in place around the radiator cowling and bonnet slam-panel?
A faulty EGR would do this on a diesel, but not so likely on a petrol, as EGR is mapped to lower speeds/loads only on a diesel.
Do you have any figures for exhaust gas temperature when this is happening?
|
|
|
Post by shaggydog007 on May 19, 2015 17:51:29 GMT 1
Thanks for feedback
Car was not used that much last year but has been fine upuntil about 1 mth ago.
Air cond in front of rad and small oil cooler attached to air con
Car has bigger turbo and other engine mods running over 300bhp.
I agree partial blockage might be the case how do i test for this or what do i put in it to clear it as a next step?
|
|
|
Post by Karl on May 19, 2015 19:19:20 GMT 1
Vacuum fill coolant device should rule out any air locks
|
|
|
Post by Monkey on May 19, 2015 19:26:17 GMT 1
The bigger turbo isn't cooking the cooling system is it?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 19, 2015 20:43:39 GMT 1
I think its a case of square pistons
|
|
|
Post by Noberator on May 19, 2015 20:55:35 GMT 1
May be the current cooling system can't cope with the demands of the engine under load or the water pump can't deliver the appropriate flow rate for the demands it needs to. 300 bhp is a huge increase from standard form and I'm inclined to agree with Chippie the cylinder head could well be warped leading to head gasket failure. Just to add is the radiator standard and not an upgraded one and is the thermostat a standard one and not one that opens earlier to aid and reducing peak temperatures.
|
|
|
Post by shaggydog007 on May 20, 2015 8:39:22 GMT 1
Its been running fine with bigger turbo and standard rad for many years.
I did put some kstop in it when i thought hg. Bad i know and ill go stand at back of the class. ::)Maybe its blocked some flow - where would this normally collect and how can i flush it out?
hg test negative for combustion gas done it 3x
|
|
|
Post by Karl on May 20, 2015 9:33:00 GMT 1
Only now you decide to mention you've put an sealing chemical in the cooling system. Yes this has likely blocked some small diameter sections I'm thinking heater matrix
|
|