snippy
|
| posted on 29/6/12 at 10:43 PM |
|
|
V8 overheating why?
I`ve posted before about the plumbing on my Rover V8 and not being too happy with it. It`s now suffering with overheating issues. I have fitted a new
thermostat, new waterpump (old one had a slight leak)and a new expansion tank cap. It is plumbed in as per the diagram below.
[img] [/img]
As the temp rises the thermostat opens (causing the temp gauge to drop briefly). It then rises up to 80 or so and then overheats. What could be
causing it to overheat? I`m not convinced it`s as simple as an air lock. Any idea`s? Is it simply not circulating the water correctly?
Nick
|
|
|
|
|
Simon
|
| posted on 29/6/12 at 11:02 PM |
|
|
First thing I noticed, the vent pipe from top of expansion tank should be vented to air - it's only used when presure in exp tank overcomes
pressure relief spring in cap - the way you have it, pressure can't be released.
From what I remember of mine, the bottom exp tank pipe was connected to the under manifold pipe straight to water pump; top hose (from thermostat) to
top of rad,(as you have and bottom hose to water pump. Vent from top of rad (assuming you are using polo rad) to t piece in top hose was what I
did.
Have a look in my archive, there may be a pic of two of help.
ATB
Simon.
|
|
|
wilkingj
|
| posted on 29/6/12 at 11:03 PM |
|
|
1. Big enough Radiator / enough airflow and a cowling in the nosecone to prevent the air bypassing the radiator?
2. Do you have the Bypass hose fitted? ie the one that used to feed the heater from the back of the head (inlet manifold water jacket)?
EDIT:
I have always used EXACTLY the same amount of water, regardless of a 10 mile visit to town or a 100 mile trip to Stoneleigh / Newark.
I fixed that by fitting a Rad Cap from a late Series 3 Land Rover (15Psi). These have TWO seals in them. The usual one in the rad, and a flat plain
rubber seal in the very top of the cap.
This allows water to pass thru the cap and still maintains a seal. I feed the overflow pipe into the BOTTOM of a container (coke bottle at the moment)
The water expands, (half) fills the coke bottle. Then on cooling the second seal in the rad cap allows the rad to draw / suck back the water into the
header tank as it does with the S3 Landy.
This has solved my water usage problem. I just need a flashy bottle to replace the plastic coke bottle, which has proved my solution to my problem
works.
I have 3 pipes on my header tank.
the lower outlet in the header tank goes to near the water pump ie the feed from the header tank to the water pump / inlet
From the top hose there is a small pipe to the top of the header tank (NOT the header tank overflow) this is for the return / air bubbles to be
returned to the header tank (also this pipe could come form a water swirl tank)
The I have the overflow pipe (above the rad cap seal) which goes into my coke bottle.
Just another thought!
Cheers
[Edited on 29/6/2012 by wilkingj]
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
|
|
|
rusty nuts
|
| posted on 30/6/12 at 07:31 AM |
|
|
Try connecting the blanked off connections , it might be worth fitting a bleed of some sort to aid filling the system . My old P6 Rover had a bleed
off point from the inlet manifold that was connected to the top of the rad which used to get blocked, cleaning it helped. Also I see no mention of a
fan of any sort?
|
|
|
robinj66
|
| posted on 30/6/12 at 07:59 AM |
|
|
I'm assumoing RV8 - what inlet manifold are you using? There has been mention on the Cobra forum that one of the Edelbrock inlet manifolds
needs a hole drilled somewhere to prevent "hot spots"
|
|
|
snippy
|
| posted on 30/6/12 at 09:51 PM |
|
|
Wilkingj – The rad fills the nose cone so no issues with air bypassing it. As for bypass hose, probably not as I have 2 connections blanked off as per
the diagram.
My expansion tank only has two outlets, upper & lower but both below the cap. I`d say the upper is the return feed back into the tank. When the
car warms up the water level in the tank rises right up to the cap and the pressure has blown water out of the cap!
I`m wondering whether to `T` in the blanked off pipe from the back of the water pump with the bottom pipe from the expansion tank? or `T` in the
blanked off pipe on the rear end of the manifold with the bottom pipe from the expansion tank?
Rusty Nuts – I do have a fan which has manual over ride
Robinj66 – I`m using an Edelbrock performance manifold due to fitting an Edelbrock carb.
I`m thinking I have a build up of pressure in my system causing it to overheat, any thoughts?
|
|
|
robinj66
|
| posted on 1/7/12 at 01:05 PM |
|
|
This link might help (taken from the Cobra Club forum). You might also want
to do a search under "performer manifold" on the same site
|
|
|
.jpg)
