Estima Motoring Community
News:
 
*
Welcome, Guest. Please login or register. May 15, 2012, 12:55:48 AM


Login with username, password and session length


Don't forget to have a look at our website at www.estima-motoring.co.uk
Pages: [1]   Go Down
  Print  
Author Topic: Previa foam in expansion tank  (Read 993 times)
0 Members and 1 Guest are viewing this topic.
mace
1st gear user
*
Offline Offline

Posts: 15



« on: November 29, 2010, 09:51:24 PM »

I've bought a 2.4 previa 1995 M reg recently, to turn into a camper following the slow and painful death of my 1974 vw camper.  Happy days i thought found one with 119,000 miles on it the guy had owned it since 2002 all history to back up the mialage. ive gutted it out started the work on it but for some reason while i was running it the other day i took the expansion tank off and soap bubbles were there larger on top not like the creamy brownish foam you generally get with HG failure, its proper white and doesnt go too crazy it stays quite shallow and as the engine heats up dissapears. Now thats all i can think about and work has stopped on it till i'm happy.  taking it to a garage is not possible its not in a position were it can be moved at the moment. 
Basicly does the water cycle through the cooling system on a previa from cold (as in the water just stirring above the water inlet pipe)? this is what causes it to foam.. does water pump speed up as you rev engine? as you can tell i'm no mechanic. my supra water doesnt move ever but the engines are not even similar.. and if it was head gasket does the foam caused by exhaust gas entering coolant dissapear when the water is at running temperature? There are no other symptoms no exhaust smoke, water is clear, no oil water mix or water loss and no overheating, but i wont sleep till i know!
thanks
Logged
ADarbon
Veggie power
Global Moderator
Hyperdrive user
*****
Offline Offline

Gender: Male
Posts: 4,890


Dentey the veg bus


« Reply #1 on: November 30, 2010, 06:40:13 AM »

is there any coolent in there. if it just water that would explain the frothing. i would have expected it too be a nice blue or red colour. you can get a garage to do a pressure test and a gasses test if you are worried. but it may just need a water change and proper coolent added
Logged

Tony the family guy
Kernowman
Hold onto your nuts lads...this place is full of A.P.E.S.
Silverback
Warp drive user
*******
Offline Offline

Gender: Male
Posts: 11,539


Formerly known as....... PGR ポール


« Reply #2 on: November 30, 2010, 09:42:58 AM »

You could flush the coolant system and refill with new water.... as Tony mentioned, it could be old coolant that needs refreshing/replacing.
I'd flush it and refill... use tap water for the flush to save on antifreeze cost. But once happy it's clean and no problems I'd drain and refill with de-ionised water & antifreeze. The de-ionised water will not fur up the waterways as you use engine, unlike most tap water.
Logged



 2012 meets season... check out MEET area for events...we might be near you.
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #3 on: November 30, 2010, 08:41:09 PM »

thanks for replys
At the moment its blue coolant in there but i'm not sure of the age or quality, i'll get a thermostat as well as i'm wondering wether the coolant should be curculating from cold? i'll flush it out its the only way to know.. I hope its not HG!
Logged
propnut
4th gear user
****
Offline Offline

Posts: 749


« Reply #4 on: December 03, 2010, 07:59:35 PM »

A soapy foam can be a sure sign that someone has put radweld or similar in the water jacket to hide a HG problem. Look for any evidence of very fine copper flecks. HG is not a hard job on the Previa if you have done a HG before on any DOHC engine.
Logged
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #5 on: December 03, 2010, 10:01:24 PM »

If i flushed the system and ran the car it should blow the gasket fairly quickly?? i might have a go at the headgasket, ive changed engines clutches etc once i did a cavalier 8v? but its either me or it goes to scrap as its only worth about �350.. only thing im worried about is the timing chain as i've never dealt with one of those before?
Logged
bionic belcher
5th gear user
*****
Offline Offline

Gender: Male
Posts: 1,492


USED TO BE MONSIGNA


« Reply #6 on: December 04, 2010, 10:32:52 AM »

has someone with very little knowledge of cars possibly put screen wash in the header? thats what i thought straight away....its a resevoir....easy accessable....someone could have put some in there, just an idea

regards ade.  Grin
Logged

If It's Not Broke.... Dont Try To Fix-It. (like me....DoH!)
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #7 on: December 04, 2010, 04:50:10 PM »

Right, been over the car today it does have the coppery flecks on the inside of the expansion tank (all up the sides) but not in the water the water is clear and it had a new radiator according to a sticker but that was about 3- 4 years ago (but that was only about 12,000 miles ago) so the rad was leaking then and radweld was probably used as a temp fix.. is it possible redweld is sitting in my water system causing the frothing on its own? and if so shouldnt i be trying to get rid of it or just forget this now?
Logged
ADarbon
Veggie power
Global Moderator
Hyperdrive user
*****
Offline Offline

Gender: Male
Posts: 4,890


Dentey the veg bus


« Reply #8 on: December 04, 2010, 06:15:31 PM »

Although the previa is very good for not having head problems there is a good chance the one you got has over heated at some point due to the blocked radiator. and caused the HG to blow or even warp the head. on the other hand you could find that doing a flush and clean of the water system could solve the problem. for now get a cheep antifreeze and dionised water from asda and use that after the flush check in a couple of days what happens if its still frothing fix or sell.
Logged

Tony the family guy
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #9 on: December 04, 2010, 08:29:47 PM »

I think i'm avoiding the obvious, i've been done.. but i wouldn't sell it i'd do the right thing and make sure it doesnt bother anyone else...  but its still fine at the moment so I will not flush it and keep driving for now.. thanks for the help  Wink
Logged
Dazzler
Global Moderator
Hyperdrive user
*****
Offline Offline

Gender: Male
Posts: 4,329


« Reply #10 on: December 05, 2010, 02:50:13 PM »

As Propnut mentioned, the copper flecks are most likely K-seal or Rad weld type product.
Logged
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #11 on: December 05, 2010, 05:01:51 PM »

Yes its definatly had some put in either recently or at some point, i think it probably is HG, also it seams to accumilate a small amount of bluey green scum in the corner of the expansion tank, so i think the coolent is not to happy?.. but can anyone just confirm when you rev the engine, does the water inlet pipe that goes into the expansion tank pump the water in faster or am I seeing exhaust gas? can anyone confirm this is not normal or normal?
But ive decided if it has gone im going to bite the bullet and do it, i've done pretty much everything else when it comes to cars.. and i dont need it till april anyway are there any good reference guides etc, it all helps..
cheers!
Logged
propnut
4th gear user
****
Offline Offline

Posts: 749


« Reply #12 on: December 08, 2010, 02:46:58 PM »

All cars are the same. With the thermostat fully open you should see the water level drop slightly as you rev the engine. This is due to the impellers taking water out of the expansion bottle faster than it returns. If the water level rises you have a blockage or excess pressure. Buy a simple gas tester/HG test kit off ebay and test. This comprises a bottle of fuel, a funnel and a rubber pump valve. You get the engine to operating temp, open the expansion bottle add the liquid to the funnel tube place the tube in the expansion bottle neck and use the bulb to suck air from the expansion bottle through the fluid. If the fluid changes colour you have exhaust gases in your water jacket and therefore a blown HG. Previa heads do not crack and the job is not hard. Buy the Chilton workshop manual. DO NOT use the haynes one as it negelects to tell you to add sealent to a specific portion of the head near the cam chain.
Logged
mace
1st gear user
*
Offline Offline

Posts: 15



« Reply #13 on: December 27, 2010, 01:55:55 PM »

Thanks Propnut, on mine the thermostat doesnt have to be open the water pressure is active from cold?!?, it appears my thermostat at best is not working or is at worst is removed. I'll take that on first as it may solve the mystery straight away and overheat it....  Looking at it, being honest it looks the worst job in the world working on that engine (without a ramp anyway) but I would definatly try..
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.16 |SMF © 2011, Simple Machines

Valid XHTML 1.0! Valid CSS! Dilber MC Theme by HarzeM