coolant dropping but no leaks and egr valve

[LexVRS]

no leaks in the coolant system but its dropping, however when i open the cap theres a big hiss of presure and the level returns to more or less normal....any sugestions

also need a new egr valve as its all clogged up could this be causing the engine to get very hot/rev itself randomly while idleing

[dfullb]

no leaks in the coolant system but its dropping, however when i open the cap theres a big hiss of presure and the level returns to more or less normal....any sugestions

also need a new egr valve as its all clogged up could this be causing the engine to get very hot/rev itself randomly while idleing

What year ? Engine Type ?

Egr valve could be causing the hunting .. As for the coolant, if there are defo no leaks then your looking at head gasket .. Time to get a good garage to do a coolant pressure test & combustion leak test Etc. This will confirm .. As for the hiss when removing the cap, If the car is warm, you will definately get that any way, sometimes still appears on a cold/cool engine.

I would attempt to clean the Egr first & see if it gets better.

Dean

Edited 27 July, 2010 by dfullb

[LexVRS]

1.4 16v 2000 x reg,

it doesent haave a had gasket but ive already had the seal redone and piston rings ect ect .

the coolant seems to be under very high presure like there isnt a vacume, the thing thats confusing me is it retuns to normal and the coolant light goes off when you open the cap, also there seems to be a bit of a flat spot i expect thats down to the egr valve aswell

[MoggyTech]

Head gasket for sure.

[anewman]

Coolant leaks are not always obvious, sometimes the coolant can boil away or only spray out in a difficult to see location when under pressure. To get at the piston rings would, I'd have thought, require replacement of the headgasket.

Edited 27 July, 2010 by anewman

[LexVRS]

yh as i said on that engine there isnt a head gasket iits a silicone seal between the top and bottom half, it was all done by skoda themselfs. they looked at the coolent leak after i took it in and said they couldnt find any leaks

[Guest BigJase88]

do you have to top it up at all?

Edited 27 July, 2010 by BigJase88

[LexVRS]

just a bit once evry month or a 2

[gallego1968]

I had this on mine, but the wife wrote the car off so didn't need to do the job.

[Soot1e]

yh as i said on that engine there isnt a head gasket iits a silicone seal between the top and bottom half, it was all done by skoda themselfs. they looked at the coolent leak after i took it in and said they couldnt find any leaks

A silicone seal? Could this be a Pikey mod by Skoda themselves? Haven't heard of this fix before.

[LexVRS]

basicaly the 1.4 16v is the same engine in the polo, the 2 halves of metal ar clamped togeter so no head gastket can be fitted so its sealed fith a flexible sealant that acts as a head gasket so ive been told

[LexVRS]

im slightly more concerned about the egr because i recon its causing a flat spot in the rev range thats realy hampering when pulling off

[MoggyTech]

It's the rocker cover than uses silicon sealant, the head to block does have a gasket, or at least should have,

[Soot1e]

My mate has a Seat Ibiza 1.4, so I'll have to have a look at his and find out for myself. Tend to agree with Moggy though, just because he's Old Skool.

[LexVRS]

well i know they did the head and rocker the took the whole engine apart as some cowboy before had flumped up the timing by replacing just one cam belt not the 2 and messed evrything up!

[LexVRS]

its a puzeler mite try a new expansion tank as this one is caked in muck

[tag1_uk]

You say the expansion tank is dirty - on the inside or outside? If on the inside then that would point more to head gasket issues as that could indicate oil getting into the coolant water. If the head has been off to deal with piston ring/timing issues then I'd be more concerned about the head gasket too in case it hasn't been put back together correctly. If the engine is over heating that concerns me - was the water pump replaced when the timing belts were last done? It might be an idea to get that checked and invest in a new thermostat and temperature sender. I one had the coolant system on mine pressure checked which you could pay to get done along with a general engine compression test. The otherwise poor running/surging idle is common with this engine - see previous posts of mine but principally you need to clean the breather hose and throttle, do a throttle realignment, run a few tanks of super unleaded petrol/redex and take it for a good hard drive.

Edited 29 July, 2010 by tag1_uk

[LexVRS]

a good while ago i had a radiator leak and to slow it down i put radweld in, the bits have clogged upt the top of the expansion tank, it does look mucky on the inside but it was before all the engine work was done. the car is not overheating its bang on just below the middle of the dial so 90 i think, but i have been told that a fualty egr valve can cause the engine to get hot.

i will give it a good thrashing but the throttle body has been cleaned, i spent a good 3k on this car getting it fixed with its central locking faults and all the engine issues i would have sold it but i couldnt live with myself knowing i sold on a dodgy car and got next to nothing for it at least this way when i do sell it i will get an ok return (around what i paid for it in the first place) mind you for a car that had 50k and was only 1.3k i should have known problems would come up but its a good replacement to the first car that was written off due to foul play in an injsurance scam!!