Cooling Problems???
Cooling Problems???
Author
Discussion

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
Hi there

Some advice please.

Fans appear to be running constantly after they atart up. The Otter switch does work because they do stop when it cools down. I don't trust the temp gauge as it never seems to get above 70 degC (Or could this be a potential problem??)
The swirl pot is full. The expansion is also full. There is heat in the cab, so guess the matrix is full.
The radiator looks to be clear ie no leaves etc blocking cooling.
I have gotten hold of one of those IR temp devices where you point the laser and read the temp.

What is my best plan of faultfinding this. Using the temp gage at first glance the swirl pot seems very hot, yet the rad inlet out are not.

Any help appreciated

Rgds

Phil

im

34,302 posts

248 months

Wednesday 9th April 2008
quotequote all
philmccann said:
I don't trust the temp gauge as it never seems to get above 70 degC (Or could this be a potential problem??)
I wouldn't expect the temp to go above 70 deg C when your moving along at a normal pace. When you get stuck in traffic etc it should then rise to 85-90 deg C before the fans kick in and keep it at 85-90 until you at least start moving forward at a good pace again whereupon it should drop back to 70 (ish).

If your in a big city like London I'd expect you to see the 90 deg C reading quite a lot as you glance down but in the country I normally only ever see 70 deg C.

IMHO.

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
Hi, Thx for that

The gauge is still @ 70degC with the fans running. Even when moving I can hear the fans running. The swirl pot seems to be the hottest part. Took the lid off the swirl pot and it's full of water. The pipe enters from above the swirl pot so this can't be full of water (or it would pour out!!) is this correct.
Took the bleed screw form the rad top, nothing came out till I took the lid off the swil pot then a gulp of water came out.

StreetDragster

1,575 posts

249 months

Wednesday 9th April 2008
quotequote all
When you say the expansion tank is full, do you mean to the brim? It should be around 1/3-1/2 full when cold

Thanks

Matt

chimalsu

279 posts

269 months

Wednesday 9th April 2008
quotequote all
swirl pot should be full of water, expansion tank should have 2inches to half full of water not full as theres nowhere for water to expand to.what does ir gauge read

im

34,302 posts

248 months

Wednesday 9th April 2008
quotequote all
I've always been told by my TVR specialist to have the swirl pot about half-full when cold.

I would expect the temp to read 70 deg C with the fan running at certain points in a journey perhaps but not for long ie:

1. Car reaches 85-90 when (say) stuck in a little traffic
2. Fans kick in
3. You move off a begin to travel at a fair lick (say) 30mph whereupon
4. Air cooling the radiator (from road speed) together with the fans being on bring the temp down to 70c before...
5. The fans switch off

It's at the end of point 4 above I'd say you might see 70c with the fans on for a minute a two.

Although I have one, I'm not mechanically au-fait with these cars so perhaps someone else can step in to help you further.

chimalsu

279 posts

269 months

Wednesday 9th April 2008
quotequote all
im, there should be no air in the swirl,that would mean air in the system and not work properly,the sequence is pretty much as youve said but i find once the fans have kicked in and switched off it takes some distance at a decent speed to bring the temp down to 70 especially in summer

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
OK, this time syphoned some off the expansion to around half full. Checked swirl, about 11/2 from top. Topped this up.

Ran the engine and het up till eventually fans kicked in. Going by the IR gauge around 100degC. Fans did not appear to be blowing very hot air through. Swirl pot too hot to touch. Rad top swirl side hot. Rad top other side cool enough to touch.

Circulation???? How do I prove it??

im

34,302 posts

248 months

Wednesday 9th April 2008
quotequote all
chimalsu said:
im, there should be no air in the swirl,that would mean air in the system and not work properly,the sequence is pretty much as youve said but i find once the fans have kicked in and switched off it takes some distance at a decent speed to bring the temp down to 70 especially in summer
Sorry NOT swirl pot - I of course meant to say the Expansion tank...doh!


HRG

72,863 posts

270 months

Wednesday 9th April 2008
quotequote all
philmccann said:
OK, this time syphoned some off the expansion to around half full. Checked swirl, about 11/2 from top. Topped this up.

Ran the engine and het up till eventually fans kicked in. Going by the IR gauge around 100degC. Fans did not appear to be blowing very hot air through. Swirl pot too hot to touch. Rad top swirl side hot. Rad top other side cool enough to touch.

Circulation???? How do I prove it??
Is the rad bleed valve on the top in the same as the Griff? Sounds like yours is cool right by the bleed valve!

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
Yes cool at the bled valve side. Cool enough to touch. Swirl pot is red hot!! Hot water doesn't seem to be getting to the rad, otherwise I'm sure the air blown by the fans would be hotter.

HRG

72,863 posts

270 months

Wednesday 9th April 2008
quotequote all
philmccann said:
Yes cool at the bled valve side. Cool enough to touch. Swirl pot is red hot!! Hot water doesn't seem to be getting to the rad, otherwise I'm sure the air blown by the fans would be hotter.
Sounds exactly like an air lock to me. Have you got The Bible? I'd be inclined to go through the bleeding/refilling procedure.

StreetDragster

1,575 posts

249 months

Wednesday 9th April 2008
quotequote all
Whilst i'd follow the other guys suggestions at trying to remove any air locks, i had a similar problem on a kit car which turned out to be the water pump, something to bearing mind anyway

Thanks

Matt

chrispitman

742 posts

285 months

Wednesday 9th April 2008
quotequote all
I wonder if you have a dodgy stat, the swirl pot has two pipes bottom to rad the top off the engine trace that pipe back and the metal piece it attaches to which is bolted to the inlet manifold contains the thermostat. This is closed when the engine is cold to warm the block up quicker and then opens pushing water around the system ie the rad, if this is jamed/broke then you would get restricted flow. But the engine would get hot quick.

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
Thermostat is probably the first stop. Bleeding the second and water pump the last. The car has been laid up for the winter and this is it just coming out. Everything was ok before so it is since the lay up. Thermostat methinks and hopefully that is it.
Is it OK (temporarily) to remove the thermostat? Just to prove it at no immediate cost?

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
Just a thought

Would the swirl pot be hot if the thermostat was stuck?

Another, I would have thought that the system would be full of water. When opening the swirl pot I would have thought the contents of the overhead pipe would have spilled out. Taking the swirl pot lid off I can hear a faint sound of air escaping.

Just trying to supply as much info as poss, if anyone can make sense of it.

Rgds

Phil

tvrbob

11,197 posts

286 months

Wednesday 9th April 2008
quotequote all
im said:
I've always been told by my TVR specialist to have the swirl pot about half-full when cold.
I assume you mean the expansion pot. The swirl pot must always be full.

im

34,302 posts

248 months

Wednesday 9th April 2008
quotequote all
tvrbob said:
im said:
I've always been told by my TVR specialist to have the swirl pot about half-full when cold.
I assume you mean the expansion pot. The swirl pot must always be full.
Please see my last post - 9 entries above...

philmccann

Original Poster:

430 posts

231 months

Wednesday 9th April 2008
quotequote all
If the pipe above the swirl pot contains air, what is the purpose of the swirl pot? As I said when opening the pot I can hear air coming out, but I would have expected the complete system to be full of water and water to come out when the swirl pot is opened, This does not happen.

tvrbob

11,197 posts

286 months

Wednesday 9th April 2008
quotequote all
philmccann said:
If the pipe above the swirl pot contains air, what is the purpose of the swirl pot?
The swirl pot is aptly named. It is designed to induce separation of air from the coolant. There are several things going on in there, the diameter is larger than the pipes and so the residence time of the coolant is increased giving more time for the air to settle out. The coolant feed causes it to swirl around (hence the name). This encourages the small bubbles to combine making bigger bubbles that can move upwards more easily.

It is true that when air has entered the system that it will find its way into the top hose. The swirl pot breaths air out and water in via the expansion tank when the coolant is going through heat cycles. The outward breathing is during heat up and at that time the water pump will be moving water and priming the top hose. When the engine is cooling it will be breathing water in from the expansion tank.

If this is a problem during priming then fill the swirl pot and put the cap on then massage the top hose. This will fill the top hose with coolant and you'll find it stays full even when you open the swirl pot because the system goes into hydraulic lock. You can then top up the swirl pot as required.